qcodes.instrument_drivers.stanford_research package
Submodules
qcodes.instrument_drivers.stanford_research.SG384 module
- class qcodes.instrument_drivers.stanford_research.SG384.SRS_SG384(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument.visa.VisaInstrument
This is the code for SG384 RF Signal Generator Status: beta version Includes the essential commands from the manual
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
qcodes.instrument_drivers.stanford_research.SR560 module
- class qcodes.instrument_drivers.stanford_research.SR560.SR560(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument.base.Instrument
This is the qcodes driver for the SR 560 Voltage-preamplifier.
This is a virtual driver only and will not talk to your instrument.
Note:
The
cutoff_lo
andcutoff_hi
parameters will interact with each other on the instrument (hi cannot be <= lo) but this is not managed here, you must ensure yourself that both are correct whenever you change one of them.gain
has a vernier setting, which does not yield a well-defined output. We restrict this driver to only the predefined gain values.
- get_idn() Dict[str, Optional[str]] [source]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low level method to write to the hardware and return a response.
Subclasses that define a new hardware communication should override this method. Subclasses that transform
cmd
should instead overrideask
.- Parameters
cmd – The string to send to the instrument.
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- close() None
Irreversibly stop this instrument and free its resources.
Subclasses should override this if they have other specific resources to close.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = False, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If
True
, update the state by querying the instrument. If None update the state if known to be invalid. IfFalse
, just use the latest values in memory and never update state.params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low level method to write a command string to the hardware.
Subclasses that define a new hardware communication should override this method. Subclasses that transform
cmd
should instead overridewrite
.- Parameters
cmd – The string to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
- class qcodes.instrument_drivers.stanford_research.SR560.VoltageParameter(measured_param: qcodes.instrument.parameter.Parameter, v_amp_ins: qcodes.instrument_drivers.stanford_research.SR560.SR560, name: str = 'volt', snapshot_value: bool = True)[source]
Bases:
qcodes.instrument.parameter.MultiParameter
Amplified voltage measurement via an SR560 preamp and a measured voltage.
To be used when you feed a voltage into an SR560, send the SR560’s output voltage to a lockin or other voltage amplifier, and you have the voltage reading from that amplifier as a qcodes parameter.
VoltageParameter.get()
returns(voltage_raw, voltage)
- Parameters
measured_param – a gettable parameter returning the voltage read from the SR560 output.
v_amp_ins –
an SR560 instance where you manually maintain the present settings of the real SR560 amp.
Note: it should be possible to use other voltage preamps, if they define parameters
gain
(V_out / V_in) andinvert
(bool, output is inverted)name – the name of the current output. Default ‘volt’. Also used as the name of the whole parameter.
- get_raw() Tuple[Any, Any] [source]
get_raw
is called to perform the actual data acquisition from the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifget_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aget
method on the parameter instance.
- property full_name: str
Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this:
instrument_submodule_parameter
.
- property full_names: Tuple[str, ...]
Names of the parameter components including the name of the instrument and submodule that the parameter may be bound to. The name parts are separated by underscores, like this:
instrument_submodule_parameter
- get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]
Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.
- Parameters
value – target value
step – maximum step size
- Returns
List of stepped values, including target value.
- property instrument: Optional[InstrumentBase]
Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use
root_instrument()
to get the real instrument.
- property inter_delay: float
Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.
- Getter
Returns the current inter_delay.
- Setter
Sets the value of the inter_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the parameter. This is identical to
short_name()
.
- property post_delay: float
Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.
- Getter
Returns the current post_delay.
- Setter
Sets the value of the post_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- property raw_value: Any
Note that this property will be deprecated soon. Use
cache.raw_value
instead.Represents the cached raw value of the parameter.
- Getter
Returns the cached raw value of the parameter.
- restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext
Use a context manager to restore the value of a parameter after a
with
block.By default, the parameter value may be changed inside the block, but this can be prevented with
allow_changes=False
. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.Example
>>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.restore_at_exit(): ... p.set(3) ... print(f"value inside with block: {p.get()}") # prints 3 >>> print(f"value after with block: {p.get()}") # prints 2 >>> with p.restore_at_exit(allow_changes=False): ... p.set(5) # raises an exception
- property root_instrument: Optional[InstrumentBase]
Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use
instrument()
to get the channel.
- set_raw(value: Any) None
set_raw
is called to perform the actual setting of a parameter on the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifset_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aset
method on the parameter instance.
- set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext
Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with
allow_changes=True
.Examples
>>> from qcodes import Parameter >>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.set_to(3): ... print(f"p value in with block {p.get()}") # prints 3 ... p.set(5) # raises an exception >>> print(f"p value outside with block {p.get()}") # prints 2 >>> with p.set_to(3, allow_changes=True): ... p.set(5) # now this works >>> print(f"value after second block: {p.get()}") # still prints 2
- property setpoint_full_names: Optional[Sequence[Sequence[str]]]
Full names of setpoints including instrument names, if available
- property short_name: str
Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to
full_name()
.
- property short_names: Tuple[str, ...]
short_names is identical to names i.e. the names of the parameter parts but does not add the instrument name.
It exists for consistency with instruments and other parameters.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).If the parameter has been initiated with
snapshot_value=False
, the snapshot will NOT include thevalue
andraw_value
of the parameter.- Parameters
update – If True, update the state by calling
parameter.get()
unlesssnapshot_get
of the parameter isFalse
. Ifupdate
isNone
, use the current value from thecache
unless the cache is invalid. IfFalse
, never callparameter.get()
.params_to_skip_update – No effect but may be passed from superclass
- Returns
base snapshot
- property step: Optional[float]
Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.
- Getter
Returns the current stepsize.
- Setter
Sets the value of the step.
- Raises
TypeError – if step is set to not numeric or None
ValueError – if step is set to negative
TypeError – if step is set to not integer or None for an integer parameter
TypeError – if step is set to not a number on None
- property underlying_instrument: Optional[InstrumentBase]
Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.
This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence
root_instrument
of the parameter cannot be thehardware_instrument
, howeverunderlying_instrument
can be implemented to return thehardware_instrument
.By default it returns the
root_instrument
of the parameter.
- validate(value: Any) None
Validate the value supplied.
- Parameters
value – value to validate
- Raises
TypeError – If the value is of the wrong type.
ValueError – If the value is outside the bounds specified by the validator.
qcodes.instrument_drivers.stanford_research.SR830 module
- class qcodes.instrument_drivers.stanford_research.SR830.ChannelBuffer(name: str, instrument: qcodes.instrument_drivers.stanford_research.SR830.SR830, channel: int)[source]
Bases:
qcodes.instrument.parameter.ArrayParameter
Parameter class for the two channel buffers
Currently always returns the entire buffer TODO (WilliamHPNielsen): Make it possible to query parts of the buffer. The instrument natively supports this in its TRCL call.
- Parameters
name – The name of the parameter
instrument – The parent instrument
channel – The relevant channel (1 or 2). The name should should match this.
- prepare_buffer_readout() None [source]
Function to generate the setpoints for the channel buffer and get the right units
- property full_name: str
Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this:
instrument_submodule_parameter
.
- get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]
Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.
- Parameters
value – target value
step – maximum step size
- Returns
List of stepped values, including target value.
- property instrument: Optional[InstrumentBase]
Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use
root_instrument()
to get the real instrument.
- property inter_delay: float
Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.
- Getter
Returns the current inter_delay.
- Setter
Sets the value of the inter_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the parameter. This is identical to
short_name()
.
- property post_delay: float
Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.
- Getter
Returns the current post_delay.
- Setter
Sets the value of the post_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- property raw_value: Any
Note that this property will be deprecated soon. Use
cache.raw_value
instead.Represents the cached raw value of the parameter.
- Getter
Returns the cached raw value of the parameter.
- restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext
Use a context manager to restore the value of a parameter after a
with
block.By default, the parameter value may be changed inside the block, but this can be prevented with
allow_changes=False
. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.Example
>>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.restore_at_exit(): ... p.set(3) ... print(f"value inside with block: {p.get()}") # prints 3 >>> print(f"value after with block: {p.get()}") # prints 2 >>> with p.restore_at_exit(allow_changes=False): ... p.set(5) # raises an exception
- property root_instrument: Optional[InstrumentBase]
Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use
instrument()
to get the channel.
- set_raw(value: Any) None
set_raw
is called to perform the actual setting of a parameter on the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifset_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aset
method on the parameter instance.
- set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext
Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with
allow_changes=True
.Examples
>>> from qcodes import Parameter >>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.set_to(3): ... print(f"p value in with block {p.get()}") # prints 3 ... p.set(5) # raises an exception >>> print(f"p value outside with block {p.get()}") # prints 2 >>> with p.set_to(3, allow_changes=True): ... p.set(5) # now this works >>> print(f"value after second block: {p.get()}") # still prints 2
- property setpoint_full_names: Optional[Sequence[str]]
Full names of setpoints including instrument names if available
- property short_name: str
Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to
full_name()
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).If the parameter has been initiated with
snapshot_value=False
, the snapshot will NOT include thevalue
andraw_value
of the parameter.- Parameters
update – If True, update the state by calling
parameter.get()
unlesssnapshot_get
of the parameter isFalse
. Ifupdate
isNone
, use the current value from thecache
unless the cache is invalid. IfFalse
, never callparameter.get()
.params_to_skip_update – No effect but may be passed from superclass
- Returns
base snapshot
- property step: Optional[float]
Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.
- Getter
Returns the current stepsize.
- Setter
Sets the value of the step.
- Raises
TypeError – if step is set to not numeric or None
ValueError – if step is set to negative
TypeError – if step is set to not integer or None for an integer parameter
TypeError – if step is set to not a number on None
- property underlying_instrument: Optional[InstrumentBase]
Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.
This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence
root_instrument
of the parameter cannot be thehardware_instrument
, howeverunderlying_instrument
can be implemented to return thehardware_instrument
.By default it returns the
root_instrument
of the parameter.
- validate(value: Any) None
Validate the value supplied.
- Parameters
value – value to validate
- Raises
TypeError – If the value is of the wrong type.
ValueError – If the value is outside the bounds specified by the validator.
- class qcodes.instrument_drivers.stanford_research.SR830.ChannelTrace(name: str, channel: int, **kwargs: Any)[source]
Bases:
qcodes.instrument.parameter.ParameterWithSetpoints
Parameter class for the two channel buffers
- Parameters
name – The name of the parameter
channel – The relevant channel (1 or 2). The name should should match this.
- __getitem__(keys: Any) qcodes.instrument.sweep_values.SweepFixedValues
Slice a Parameter to get a SweepValues object to iterate over during a sweep
- property full_name: str
Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this:
instrument_submodule_parameter
.
- get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]
Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.
- Parameters
value – target value
step – maximum step size
- Returns
List of stepped values, including target value.
- increment(value: Any) None
Increment the parameter with a value
- Parameters
value – Value to be added to the parameter.
- property instrument: Optional[InstrumentBase]
Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use
root_instrument()
to get the real instrument.
- property inter_delay: float
Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.
- Getter
Returns the current inter_delay.
- Setter
Sets the value of the inter_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the parameter. This is identical to
short_name()
.
- property post_delay: float
Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.
- Getter
Returns the current post_delay.
- Setter
Sets the value of the post_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- property raw_value: Any
Note that this property will be deprecated soon. Use
cache.raw_value
instead.Represents the cached raw value of the parameter.
- Getter
Returns the cached raw value of the parameter.
- restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext
Use a context manager to restore the value of a parameter after a
with
block.By default, the parameter value may be changed inside the block, but this can be prevented with
allow_changes=False
. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.Example
>>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.restore_at_exit(): ... p.set(3) ... print(f"value inside with block: {p.get()}") # prints 3 >>> print(f"value after with block: {p.get()}") # prints 2 >>> with p.restore_at_exit(allow_changes=False): ... p.set(5) # raises an exception
- property root_instrument: Optional[InstrumentBase]
Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use
instrument()
to get the channel.
- set_raw(value: Any) None
set_raw
is called to perform the actual setting of a parameter on the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifset_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aset
method on the parameter instance.
- set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext
Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with
allow_changes=True
.Examples
>>> from qcodes import Parameter >>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.set_to(3): ... print(f"p value in with block {p.get()}") # prints 3 ... p.set(5) # raises an exception >>> print(f"p value outside with block {p.get()}") # prints 2 >>> with p.set_to(3, allow_changes=True): ... p.set(5) # now this works >>> print(f"value after second block: {p.get()}") # still prints 2
- property setpoints: Sequence[qcodes.instrument.parameter._BaseParameter]
Sequence of parameters to use as setpoints for this parameter.
- Getter
Returns a list of parameters currently used for setpoints.
- Setter
Sets the parameters to be used as setpoints from a sequence. The combined shape of the parameters supplied must be consistent with the data shape of the data returned from get on the parameter.
- property short_name: str
Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to
full_name()
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).If the parameter has been initiated with
snapshot_value=False
, the snapshot will NOT include thevalue
andraw_value
of the parameter.- Parameters
update – If True, update the state by calling
parameter.get()
unlesssnapshot_get
of the parameter isFalse
. Ifupdate
isNone
, use the current value from thecache
unless the cache is invalid. IfFalse
, never callparameter.get()
.params_to_skip_update – No effect but may be passed from superclass
- Returns
base snapshot
- property step: Optional[float]
Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.
- Getter
Returns the current stepsize.
- Setter
Sets the value of the step.
- Raises
TypeError – if step is set to not numeric or None
ValueError – if step is set to negative
TypeError – if step is set to not integer or None for an integer parameter
TypeError – if step is set to not a number on None
- sweep(start: float, stop: float, step: Optional[float] = None, num: Optional[int] = None) qcodes.instrument.sweep_values.SweepFixedValues
Create a collection of parameter values to be iterated over. Requires start and stop and (step or num) The sign of step is not relevant.
- Parameters
start – The starting value of the sequence.
stop – The end value of the sequence.
step – Spacing between values.
num – Number of values to generate.
- Returns
Collection of parameter values to be iterated over.
- Return type
SweepFixedValues
Examples
>>> sweep(0, 10, num=5) [0.0, 2.5, 5.0, 7.5, 10.0] >>> sweep(5, 10, step=1) [5.0, 6.0, 7.0, 8.0, 9.0, 10.0] >>> sweep(15, 10.5, step=1.5) >[15.0, 13.5, 12.0, 10.5]
- property underlying_instrument: Optional[InstrumentBase]
Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.
This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence
root_instrument
of the parameter cannot be thehardware_instrument
, howeverunderlying_instrument
can be implemented to return thehardware_instrument
.By default it returns the
root_instrument
of the parameter.
- validate(value: Any) None
Overwrites the standard
validate
method to also check the the parameter has consistent shape with its setpoints. This only makes sense if the parameter has an Arrays validatorArguments are passed to the super method
- class qcodes.instrument_drivers.stanford_research.SR830.GeneratedSetPoints(sweep_array: Iterable[Union[int, float]] = array([0., 0.11111111, 0.22222222, 0.33333333, 0.44444444, 0.55555556, 0.66666667, 0.77777778, 0.88888889, 1.]), *args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument.parameter.Parameter
A parameter that generates a setpoint array from start, stop and num points parameters.
- update_units_if_constant_sample_rate() None [source]
If the buffer is filled at a constant sample rate, update the unit to “s” and label to “Time”; otherwise do nothing
- set_raw(value: Iterable[Union[int, float]]) None [source]
set_raw
is called to perform the actual setting of a parameter on the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifset_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aset
method on the parameter instance.
- get_raw() Any [source]
get_raw
is called to perform the actual data acquisition from the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifget_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aget
method on the parameter instance.
- __getitem__(keys: Any) qcodes.instrument.sweep_values.SweepFixedValues
Slice a Parameter to get a SweepValues object to iterate over during a sweep
- property full_name: str
Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this:
instrument_submodule_parameter
.
- get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]
Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.
- Parameters
value – target value
step – maximum step size
- Returns
List of stepped values, including target value.
- increment(value: Any) None
Increment the parameter with a value
- Parameters
value – Value to be added to the parameter.
- property instrument: Optional[InstrumentBase]
Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use
root_instrument()
to get the real instrument.
- property inter_delay: float
Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.
- Getter
Returns the current inter_delay.
- Setter
Sets the value of the inter_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the parameter. This is identical to
short_name()
.
- property post_delay: float
Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.
- Getter
Returns the current post_delay.
- Setter
Sets the value of the post_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- property raw_value: Any
Note that this property will be deprecated soon. Use
cache.raw_value
instead.Represents the cached raw value of the parameter.
- Getter
Returns the cached raw value of the parameter.
- restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext
Use a context manager to restore the value of a parameter after a
with
block.By default, the parameter value may be changed inside the block, but this can be prevented with
allow_changes=False
. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.Example
>>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.restore_at_exit(): ... p.set(3) ... print(f"value inside with block: {p.get()}") # prints 3 >>> print(f"value after with block: {p.get()}") # prints 2 >>> with p.restore_at_exit(allow_changes=False): ... p.set(5) # raises an exception
- property root_instrument: Optional[InstrumentBase]
Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use
instrument()
to get the channel.
- set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext
Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with
allow_changes=True
.Examples
>>> from qcodes import Parameter >>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.set_to(3): ... print(f"p value in with block {p.get()}") # prints 3 ... p.set(5) # raises an exception >>> print(f"p value outside with block {p.get()}") # prints 2 >>> with p.set_to(3, allow_changes=True): ... p.set(5) # now this works >>> print(f"value after second block: {p.get()}") # still prints 2
- property short_name: str
Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to
full_name()
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).If the parameter has been initiated with
snapshot_value=False
, the snapshot will NOT include thevalue
andraw_value
of the parameter.- Parameters
update – If True, update the state by calling
parameter.get()
unlesssnapshot_get
of the parameter isFalse
. Ifupdate
isNone
, use the current value from thecache
unless the cache is invalid. IfFalse
, never callparameter.get()
.params_to_skip_update – No effect but may be passed from superclass
- Returns
base snapshot
- property step: Optional[float]
Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.
- Getter
Returns the current stepsize.
- Setter
Sets the value of the step.
- Raises
TypeError – if step is set to not numeric or None
ValueError – if step is set to negative
TypeError – if step is set to not integer or None for an integer parameter
TypeError – if step is set to not a number on None
- sweep(start: float, stop: float, step: Optional[float] = None, num: Optional[int] = None) qcodes.instrument.sweep_values.SweepFixedValues
Create a collection of parameter values to be iterated over. Requires start and stop and (step or num) The sign of step is not relevant.
- Parameters
start – The starting value of the sequence.
stop – The end value of the sequence.
step – Spacing between values.
num – Number of values to generate.
- Returns
Collection of parameter values to be iterated over.
- Return type
SweepFixedValues
Examples
>>> sweep(0, 10, num=5) [0.0, 2.5, 5.0, 7.5, 10.0] >>> sweep(5, 10, step=1) [5.0, 6.0, 7.0, 8.0, 9.0, 10.0] >>> sweep(15, 10.5, step=1.5) >[15.0, 13.5, 12.0, 10.5]
- property underlying_instrument: Optional[InstrumentBase]
Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.
This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence
root_instrument
of the parameter cannot be thehardware_instrument
, howeverunderlying_instrument
can be implemented to return thehardware_instrument
.By default it returns the
root_instrument
of the parameter.
- validate(value: Any) None
Validate the value supplied.
- Parameters
value – value to validate
- Raises
TypeError – If the value is of the wrong type.
ValueError – If the value is outside the bounds specified by the validator.
- class qcodes.instrument_drivers.stanford_research.SR830.SR830(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument.visa.VisaInstrument
This is the qcodes driver for the Stanford Research Systems SR830 Lock-in Amplifier
- SNAP_PARAMETERS = {'aux1': '5', 'aux2': '6', 'aux3': '7', 'aux4': '8', 'ch1': '10', 'ch2': '11', 'freq': '9', 'p': '4', 'phase': '4', 'r': '3', 'x': '1', 'y': '2', 'θ': '4'}
- snap(*parameters: str) Tuple[float, ...] [source]
Get between 2 and 6 parameters at a single instant. This provides a coherent snapshot of measured signals. Pick up to 6 from: X, Y, R, θ, the aux inputs 1-4, frequency, or what is currently displayed on channels 1 and 2.
Reading X and Y (or R and θ) gives a coherent snapshot of the signal. Snap is important when the time constant is very short, a time constant less than 100 ms.
- Parameters
*parameters – From 2 to 6 strings of names of parameters for which the values are requested. including: ‘x’, ‘y’, ‘r’, ‘p’, ‘phase’ or ‘θ’, ‘aux1’, ‘aux2’, ‘aux3’, ‘aux4’, ‘freq’, ‘ch1’, and ‘ch2’.
- Returns
A tuple of floating point values in the same order as requested.
Examples
>>> lockin.snap('x','y') -> tuple(x,y)
>>> lockin.snap('aux1','aux2','freq','phase') >>> -> tuple(aux1,aux2,freq,phase)
Note
Volts for x, y, r, and aux 1-4 Degrees for θ Hertz for freq Unknown for ch1 and ch2. It will depend on what was set.
If X,Y,R and θ are all read, then the values of X,Y are recorded approximately 10 µs apart from R,θ. Thus, the values of X and Y may not yield the exact values of R and θ from a single snap.
The values of the Aux Inputs may have an uncertainty of up to 32 µs.
The frequency is computed only every other period or 40 ms, whichever is longer.
- increment_sensitivity() bool [source]
Increment the sensitivity setting of the lock-in. This is equivalent to pushing the sensitivity up button on the front panel. This has no effect if the sensitivity is already at the maximum.
- Returns
Whether or not the sensitivity was actually changed.
- decrement_sensitivity() bool [source]
Decrement the sensitivity setting of the lock-in. This is equivalent to pushing the sensitivity down button on the front panel. This has no effect if the sensitivity is already at the minimum.
- Returns
Whether or not the sensitivity was actually changed.
- autorange(max_changes: int = 1) None [source]
Automatically changes the sensitivity of the instrument according to the R value and defined max_changes.
- Parameters
max_changes – Maximum number of steps allowing the function to automatically change the sensitivity (default is 1). The actual number of steps needed to change to the optimal sensitivity may be more or less than this maximum.
- set_sweep_parameters(sweep_param: qcodes.instrument.parameter.Parameter, start: float, stop: float, n_points: int = 10, label: Optional[str] = None) None [source]
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
qcodes.instrument_drivers.stanford_research.SR860 module
- class qcodes.instrument_drivers.stanford_research.SR860.SR860(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument_drivers.stanford_research.SR86x.SR86x
The SR860 instrument is almost equal to the SR865, except for the max frequency
- PARAMETER_NAMES = {'P': '3', 'R': '2', 'X': '0', 'Xnoise': '8', 'Y': '1', 'Ynoise': '9', 'amplitude': '13', 'aux_in1': '4', 'aux_in2': '5', 'aux_in3': '6', 'aux_in4': '7', 'aux_out1': '10', 'aux_out2': '11', 'frequency': '15', 'frequency_ext': '16', 'phase': '12', 'sine_outdc': '14'}
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_data_channels_dict(requery_names: bool = False) Dict[str, float]
Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
- Parameters
requery_names – if False, the currently assigned parameter names will not be queries from the instrument in order to save time on communication, in this case the cached assigned parameter names will be used for the keys of the dicitonary; if True, the assigned parameter names will be queried from the instrument
- Returns
a dictionary where keys are names of parameters assigned to the data channels, and values are the values of those parameters
- get_data_channels_parameters(query_instrument: bool = True) Tuple[str, ...]
Convenience method to query a list of parameters which the data channels are currently assigned to.
- Parameters
query_instrument – If set to False, the internally cashed names of the parameters will be returned; if True, then the names will be queried through the instrument
- Returns
a tuple of 4 strings of parameter names
- get_data_channels_values() Tuple[float, ...]
Queries the current values of the data channels
- Returns
tuple of 4 values of the data channels
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- get_values(*parameter_names: str) Tuple[float, ...]
Get values of 2 or 3 parameters that are measured by the lock-in amplifier. These values are guaranteed to come from the same measurement cycle as opposed to getting values of parameters one by one (for example, by calling sr.X(), and then sr.Y().
- Parameters
*parameter_names – 2 or 3 names of parameters for which the values are requested; valid names can be found in PARAMETER_NAMES attribute of the driver class
- Returns
a tuple of 2 or 3 floating point values
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
qcodes.instrument_drivers.stanford_research.SR865 module
- class qcodes.instrument_drivers.stanford_research.SR865.SR865(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument_drivers.stanford_research.SR86x.SR86x
The SR865 instrument is almost equal to the SR860, except for the max frequency
- PARAMETER_NAMES = {'P': '3', 'R': '2', 'X': '0', 'Xnoise': '8', 'Y': '1', 'Ynoise': '9', 'amplitude': '13', 'aux_in1': '4', 'aux_in2': '5', 'aux_in3': '6', 'aux_in4': '7', 'aux_out1': '10', 'aux_out2': '11', 'frequency': '15', 'frequency_ext': '16', 'phase': '12', 'sine_outdc': '14'}
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_data_channels_dict(requery_names: bool = False) Dict[str, float]
Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
- Parameters
requery_names – if False, the currently assigned parameter names will not be queries from the instrument in order to save time on communication, in this case the cached assigned parameter names will be used for the keys of the dicitonary; if True, the assigned parameter names will be queried from the instrument
- Returns
a dictionary where keys are names of parameters assigned to the data channels, and values are the values of those parameters
- get_data_channels_parameters(query_instrument: bool = True) Tuple[str, ...]
Convenience method to query a list of parameters which the data channels are currently assigned to.
- Parameters
query_instrument – If set to False, the internally cashed names of the parameters will be returned; if True, then the names will be queried through the instrument
- Returns
a tuple of 4 strings of parameter names
- get_data_channels_values() Tuple[float, ...]
Queries the current values of the data channels
- Returns
tuple of 4 values of the data channels
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- get_values(*parameter_names: str) Tuple[float, ...]
Get values of 2 or 3 parameters that are measured by the lock-in amplifier. These values are guaranteed to come from the same measurement cycle as opposed to getting values of parameters one by one (for example, by calling sr.X(), and then sr.Y().
- Parameters
*parameter_names – 2 or 3 names of parameters for which the values are requested; valid names can be found in PARAMETER_NAMES attribute of the driver class
- Returns
a tuple of 2 or 3 floating point values
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
qcodes.instrument_drivers.stanford_research.SR865A module
- class qcodes.instrument_drivers.stanford_research.SR865A.SR865A(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument_drivers.stanford_research.SR86x.SR86x
The SR865A instrument is almost equal to the SR865, except for the max frequency
- PARAMETER_NAMES = {'P': '3', 'R': '2', 'X': '0', 'Xnoise': '8', 'Y': '1', 'Ynoise': '9', 'amplitude': '13', 'aux_in1': '4', 'aux_in2': '5', 'aux_in3': '6', 'aux_in4': '7', 'aux_out1': '10', 'aux_out2': '11', 'frequency': '15', 'frequency_ext': '16', 'phase': '12', 'sine_outdc': '14'}
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_data_channels_dict(requery_names: bool = False) Dict[str, float]
Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
- Parameters
requery_names – if False, the currently assigned parameter names will not be queries from the instrument in order to save time on communication, in this case the cached assigned parameter names will be used for the keys of the dicitonary; if True, the assigned parameter names will be queried from the instrument
- Returns
a dictionary where keys are names of parameters assigned to the data channels, and values are the values of those parameters
- get_data_channels_parameters(query_instrument: bool = True) Tuple[str, ...]
Convenience method to query a list of parameters which the data channels are currently assigned to.
- Parameters
query_instrument – If set to False, the internally cashed names of the parameters will be returned; if True, then the names will be queried through the instrument
- Returns
a tuple of 4 strings of parameter names
- get_data_channels_values() Tuple[float, ...]
Queries the current values of the data channels
- Returns
tuple of 4 values of the data channels
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- get_values(*parameter_names: str) Tuple[float, ...]
Get values of 2 or 3 parameters that are measured by the lock-in amplifier. These values are guaranteed to come from the same measurement cycle as opposed to getting values of parameters one by one (for example, by calling sr.X(), and then sr.Y().
- Parameters
*parameter_names – 2 or 3 names of parameters for which the values are requested; valid names can be found in PARAMETER_NAMES attribute of the driver class
- Returns
a tuple of 2 or 3 floating point values
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
qcodes.instrument_drivers.stanford_research.SR86x module
- class qcodes.instrument_drivers.stanford_research.SR86x.SR86x(*args: Any, **kwargs: Any)[source]
Bases:
qcodes.instrument.visa.VisaInstrument
This is the code for Stanford_SR865 Lock-in Amplifier
- PARAMETER_NAMES = {'P': '3', 'R': '2', 'X': '0', 'Xnoise': '8', 'Y': '1', 'Ynoise': '9', 'amplitude': '13', 'aux_in1': '4', 'aux_in2': '5', 'aux_in3': '6', 'aux_in4': '7', 'aux_out1': '10', 'aux_out2': '11', 'frequency': '15', 'frequency_ext': '16', 'phase': '12', 'sine_outdc': '14'}
- get_values(*parameter_names: str) Tuple[float, ...] [source]
Get values of 2 or 3 parameters that are measured by the lock-in amplifier. These values are guaranteed to come from the same measurement cycle as opposed to getting values of parameters one by one (for example, by calling sr.X(), and then sr.Y().
- Parameters
*parameter_names – 2 or 3 names of parameters for which the values are requested; valid names can be found in PARAMETER_NAMES attribute of the driver class
- Returns
a tuple of 2 or 3 floating point values
- get_data_channels_values() Tuple[float, ...] [source]
Queries the current values of the data channels
- Returns
tuple of 4 values of the data channels
- get_data_channels_parameters(query_instrument: bool = True) Tuple[str, ...] [source]
Convenience method to query a list of parameters which the data channels are currently assigned to.
- Parameters
query_instrument – If set to False, the internally cashed names of the parameters will be returned; if True, then the names will be queried through the instrument
- Returns
a tuple of 4 strings of parameter names
- get_data_channels_dict(requery_names: bool = False) Dict[str, float] [source]
Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
- Parameters
requery_names – if False, the currently assigned parameter names will not be queries from the instrument in order to save time on communication, in this case the cached assigned parameter names will be used for the keys of the dicitonary; if True, the assigned parameter names will be queried from the instrument
- Returns
a dictionary where keys are names of parameters assigned to the data channels, and values are the values of those parameters
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- ask(cmd: str) str
Write a command string to the hardware and return a response.
Subclasses that transform
cmd
should override this method, and in it callsuper().ask(new_cmd)
. Subclasses that define a new hardware communication should instead overrideask_raw
.- Parameters
cmd – The string to send to the instrument.
- Returns
response
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- ask_raw(cmd: str) str
Low-level interface to
visa_handle.ask
.- Parameters
cmd – The command to send to the instrument.
- Returns
The instrument’s response.
- Return type
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- check_error(ret_code: int) None
Default error checking, raises an error if return code
!=0
. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.- Parameters
ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py
- Raises
visa.VisaIOError – if
ret_code
indicates a communication problem.
- classmethod close_all() None
Try to close all instruments registered in
_all_instruments
This is handy for use with atexit to ensure that all instruments are closed when a python session is closed.Examples
>>> atexit.register(qc.Instrument.close_all())
- connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) None
Print a standard message on initial connection to an instrument.
- Parameters
idn_param – Name of parameter that returns ID dict. Default
IDN
.begin_time –
time.time()
when init started. Default isself._t0
, set at start ofInstrument.__init__
.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- static exist(name: str, instrument_class: Optional[type] = None) bool
Check if an instrument with a given names exists (i.e. is already instantiated).
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- classmethod find_instrument(name: str, instrument_class: Optional[Type[qcodes.instrument.base.T]] = None) qcodes.instrument.base.T
Find an existing instrument by name.
- Parameters
name – Name of the instrument.
instrument_class – The type of instrument you are looking for.
- Returns
The instrument found.
- Raises
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- get_idn() Dict[str, Optional[str]]
Parse a standard VISA
*IDN?
response into an ID dict.Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.
Override this if your instrument does not support
*IDN?
or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.- Returns
A dict containing vendor, model, serial, and firmware.
- classmethod instances() List[qcodes.instrument.base.Instrument]
Get all currently defined instances of this instrument class.
You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.
- Returns
A list of instances.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool
Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.
- Parameters
instr_instance – Instance of an Instrument class or its subclass.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: Optional[qcodes.instrument.base.InstrumentBase]
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- classmethod record_instance(instance: qcodes.instrument.base.Instrument) None
Record (a weak ref to) an instance in a class’s instance list.
Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.
This method is called after initialization of the instrument is completed.
- Parameters
instance – Instance to record.
- Raises
KeyError – If another instance with the same name is already present.
- classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None
Remove a particular instance from the record.
- Parameters
instance – The instance to remove
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- set_address(address: str) None
Set the address for this instrument.
- Parameters
address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).
- set_terminator(terminator: str) None
Change the read terminator to use.
- Parameters
terminator – Character(s) to look for at the end of a read. eg.
\r\n
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If True, update the state by querying the instrument. If None only update if the state is known to be invalid. If False, just use the latest values in memory and never update.
params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- write(cmd: str) None
Write a command string with NO response to the hardware.
Subclasses that transform
cmd
should override this method, and in it callsuper().write(new_cmd)
. Subclasses that define a new hardware communication should instead overridewrite_raw
.- Parameters
cmd – The string to send to the instrument.
- Raises
Exception – Wraps any underlying exception with extra context, including the command and the instrument.
- write_raw(cmd: str) None
Low-level interface to
visa_handle.write
.- Parameters
cmd – The command to send to the instrument.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
- class qcodes.instrument_drivers.stanford_research.SR86x.SR86xBuffer(parent: qcodes.instrument_drivers.stanford_research.SR86x.SR86x, name: str)[source]
Bases:
qcodes.instrument.channel.InstrumentChannel
The buffer module for the SR86x driver. This driver has been verified to work with the SR860 and SR865. For reference, please consult the SR860 manual: http://thinksrs.com/downloads/PDFs/Manuals/SR860m.pdf
- snapshot_base(update: Optional[bool] = False, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any] [source]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If
True
, update the state by querying the instrument. If None update the state if known to be invalid. IfFalse
, just use the latest values in memory and never update state.params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- set_capture_rate_to_maximum() None [source]
Sets the capture rate to maximum. The maximum capture rate is retrieved from the device, and depends on the current value of the time constant.
- start_capture(acquisition_mode: str, trigger_mode: str) None [source]
Start an acquisition. Please see page 137 of the manual for a detailed explanation.
- Parameters
acquisition_mode – “ONE” | “CONT”
trigger_mode – “IMM” | “TRIG” | “SAMP”
- set_capture_length_to_fit_samples(sample_count: int) None [source]
Set the capture length of the buffer to fit the given number of samples.
- Parameters
sample_count – Number of samples that the buffer has to fit
- wait_until_samples_captured(sample_count: int) None [source]
Wait until the given number of samples is captured. This function is blocking and has to be used with caution because it does not have a timeout.
- Parameters
sample_count – Number of samples that needs to be captured
- get_capture_data(sample_count: int) Dict[str, numpy.ndarray] [source]
Read the given number of samples of the capture data from the buffer.
- Parameters
sample_count – number of samples to read from the buffer
- Returns
The keys in the dictionary correspond to the captured variables. For instance, if before the capture, the capture config was set as ‘capture_config(“X,Y”)’, then the keys will be “X” and “Y”. The values in the dictionary are numpy arrays of numbers.
- capture_one_sample_per_trigger(trigger_count: int, start_triggers_pulsetrain: Callable[[...], Any]) Dict[str, numpy.ndarray] [source]
Capture one sample per each trigger, and return when the specified number of triggers has been received.
- Parameters
trigger_count – Number of triggers to capture samples for
start_triggers_pulsetrain – By calling this non-blocking function, the train of trigger pulses should start
- Returns
The keys in the dictionary correspond to the captured variables. For instance, if before the capture, the capture config was set as ‘capture_config(“X,Y”)’, then the keys will be “X” and “Y”. The values in the dictionary are numpy arrays of numbers.
- capture_samples_after_trigger(sample_count: int, send_trigger: Callable[[...], Any]) Dict[str, numpy.ndarray] [source]
Capture a number of samples after a trigger has been received. Please refer to page 135 of the manual for details.
- Parameters
sample_count – Number of samples to capture
send_trigger – By calling this non-blocking function, one trigger should be sent that will initiate the capture
- Returns
The keys in the dictionary correspond to the captured variables. For instance, if before the capture, the capture config was set as ‘capture_config(“X,Y”)’, then the keys will be “X” and “Y”. The values in the dictionary are numpy arrays of numbers.
- capture_samples(sample_count: int) Dict[str, numpy.ndarray] [source]
Capture a number of samples at a capture rate, starting immediately. Unlike the “continuous” capture mode, here the buffer does not get overwritten with the new data once the buffer is full.
The function blocks until the required number of samples is acquired, and returns them.
- Parameters
sample_count – Number of samples to capture
- Returns
The keys in the dictionary correspond to the captured variables. For instance, if before the capture, the capture config was set as ‘capture_config(“X,Y”)’, then the keys will be “X” and “Y”. The values in the dictionary are numpy arrays of numbers.
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: qcodes.instrument.base.InstrumentBase
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.
- class qcodes.instrument_drivers.stanford_research.SR86x.SR86xBufferReadout(name: str, instrument: qcodes.instrument_drivers.stanford_research.SR86x.SR86x, **kwargs: Any)[source]
Bases:
qcodes.instrument.parameter.ArrayParameter
The parameter array that holds read out data. We need this to be compatible with qcodes.Measure
- Parameters
name – Name of the parameter.
instrument – The instrument to add this parameter to.
- prepare_readout(capture_data: numpy.ndarray) None [source]
Prepare this parameter for readout.
- Parameters
capture_data – The data to capture.
- get_raw() numpy.ndarray [source]
Public method to access the capture data
- property full_name: str
Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this:
instrument_submodule_parameter
.
- get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]
Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.
- Parameters
value – target value
step – maximum step size
- Returns
List of stepped values, including target value.
- property instrument: Optional[InstrumentBase]
Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use
root_instrument()
to get the real instrument.
- property inter_delay: float
Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.
- Getter
Returns the current inter_delay.
- Setter
Sets the value of the inter_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the parameter. This is identical to
short_name()
.
- property post_delay: float
Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.
Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.
- Getter
Returns the current post_delay.
- Setter
Sets the value of the post_delay.
- Raises
TypeError – If delay is not int nor float
ValueError – If delay is negative
- property raw_value: Any
Note that this property will be deprecated soon. Use
cache.raw_value
instead.Represents the cached raw value of the parameter.
- Getter
Returns the cached raw value of the parameter.
- restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext
Use a context manager to restore the value of a parameter after a
with
block.By default, the parameter value may be changed inside the block, but this can be prevented with
allow_changes=False
. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.Example
>>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.restore_at_exit(): ... p.set(3) ... print(f"value inside with block: {p.get()}") # prints 3 >>> print(f"value after with block: {p.get()}") # prints 2 >>> with p.restore_at_exit(allow_changes=False): ... p.set(5) # raises an exception
- property root_instrument: Optional[InstrumentBase]
Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use
instrument()
to get the channel.
- set_raw(value: Any) None
set_raw
is called to perform the actual setting of a parameter on the instrument. This method should either be overwritten to perform the desired operation or alternatively forParameter
a suitable method is automatically generated ifset_cmd
is supplied to the parameter constructor. The method is automatically wrapped to provide aset
method on the parameter instance.
- set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext
Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with
allow_changes=True
.Examples
>>> from qcodes import Parameter >>> p = Parameter("p", set_cmd=None, get_cmd=None) >>> p.set(2) >>> with p.set_to(3): ... print(f"p value in with block {p.get()}") # prints 3 ... p.set(5) # raises an exception >>> print(f"p value outside with block {p.get()}") # prints 2 >>> with p.set_to(3, allow_changes=True): ... p.set(5) # now this works >>> print(f"value after second block: {p.get()}") # still prints 2
- property setpoint_full_names: Optional[Sequence[str]]
Full names of setpoints including instrument names if available
- property short_name: str
Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to
full_name()
.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).If the parameter has been initiated with
snapshot_value=False
, the snapshot will NOT include thevalue
andraw_value
of the parameter.- Parameters
update – If True, update the state by calling
parameter.get()
unlesssnapshot_get
of the parameter isFalse
. Ifupdate
isNone
, use the current value from thecache
unless the cache is invalid. IfFalse
, never callparameter.get()
.params_to_skip_update – No effect but may be passed from superclass
- Returns
base snapshot
- property step: Optional[float]
Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.
- Getter
Returns the current stepsize.
- Setter
Sets the value of the step.
- Raises
TypeError – if step is set to not numeric or None
ValueError – if step is set to negative
TypeError – if step is set to not integer or None for an integer parameter
TypeError – if step is set to not a number on None
- property underlying_instrument: Optional[InstrumentBase]
Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.
This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence
root_instrument
of the parameter cannot be thehardware_instrument
, howeverunderlying_instrument
can be implemented to return thehardware_instrument
.By default it returns the
root_instrument
of the parameter.
- validate(value: Any) None
Validate the value supplied.
- Parameters
value – value to validate
- Raises
TypeError – If the value is of the wrong type.
ValueError – If the value is outside the bounds specified by the validator.
- class qcodes.instrument_drivers.stanford_research.SR86x.SR86xDataChannel(parent: qcodes.instrument_drivers.stanford_research.SR86x.SR86x, name: str, cmd_id: str, cmd_id_name: Optional[str] = None, color: Optional[str] = None)[source]
Bases:
qcodes.instrument.channel.InstrumentChannel
Implements a data channel of SR86x lock-in amplifier. Parameters that are assigned to these channels get plotted on the display of the instrument. Moreover, there are commands that allow to conveniently retrieve the values of the parameters that are currently assigned to the data channels.
This class relies on the available parameter names that should be mentioned in the lock-in amplifier class in PARAMETER_NAMES attribute.
- Parameters
parent – an instance of SR86x driver
name – data channel name that is to be used to reference it from the parent
cmd_id – this ID is used in VISA commands to refer to this data channel, usually is an integer number
cmd_id_name – this name can also be used in VISA commands along with channel_id; it is not used in this implementation, but is added for reference
color – every data channel is also referred to by the color with which it is being plotted on the instrument’s screen; added here only for reference
- __getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.Parameter]
Delegate instrument[‘name’] to parameter or function ‘name’.
- add_function(name: str, **kwargs: Any) None
Bind one
Function
to this instrument.Instrument subclasses can call this repeatedly in their
__init__
for every real function of the instrument.This functionality is meant for simple cases, principally things that map to simple commands like
*RST
(reset) or those with just a few arguments. It requires a fixed argument count, and positional args only. If your case is more complicated, you’re probably better off simply making a new method in yourInstrument
subclass definition.- Parameters
name – How the Function will be stored within
instrument.Functions
and also how you address it using the shortcut methods:instrument.call(func_name, *args)
etc.**kwargs – constructor kwargs for
Function
- Raises
KeyError – If this instrument already has a function with this name.
- add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None
Bind one Parameter to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
for every real parameter of the instrument.In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.
- Parameters
name – How the parameter will be stored within
instrument.parameters
and also how you address it using the shortcut methods:instrument.set(param_name, value)
etc.parameter_class – You can construct the parameter out of any class. Default
parameter.Parameter
.**kwargs – Constructor arguments for
parameter_class
.
- Raises
KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.
ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.
- add_submodule(name: str, submodule: Union[InstrumentModule, ChannelTuple]) None
Bind one submodule to this instrument.
Instrument subclasses can call this repeatedly in their
__init__
method for every submodule of the instrument.Submodules can effectively be considered as instruments within the main instrument, and should at minimum be snapshottable. For example, they can be used to either store logical groupings of parameters, which may or may not be repeated, or channel lists. They should either be an instance of an
InstrumentModule
or aChannelTuple
.- Parameters
name – How the submodule will be stored within
instrument.submodules
and also how it can be addressed.submodule – The submodule to be stored.
- Raises
- property ancestors: List[qcodes.instrument.base.InstrumentBase]
Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.
- call(func_name: str, *args: Any) Any
Shortcut for calling a function from its name.
- Parameters
func_name – The name of a function of this instrument.
*args – any arguments to the function.
- Returns
The return value of the function.
- delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']
A list of names (strings) of dictionaries which are (or will be) attributes of
self
, whose keys should be treated as attributes ofself
.
- delegate_attr_objects: List[str] = []
A list of names (strings) of objects which are (or will be) attributes of
self
, whose attributes should be passed through toself
.
- get(param_name: str) Any
Shortcut for getting a parameter from its name.
- Parameters
param_name – The name of a parameter of this instrument.
- Returns
The current value of the parameter.
- invalidate_cache() None
Invalidate the cache of all parameters on the instrument. Calling this method will recursively mark the cache of all parameters on the instrument and any parameter on instrument modules as invalid.
This is useful if you have performed manual operations (e.g. using the frontpanel) which changes the state of the instrument outside QCoDeS.
This in turn means that the next snapshot of the instrument will trigger a (potentially slow) reread of all parameters of the instrument if you pass update=None to snapshot.
- load_metadata(metadata: Mapping[str, Any]) None
Load metadata into this classes metadata dictionary.
- Parameters
metadata – Metadata to load.
- property name: str
Name of the instrument This is equivalent to full_name for backwards compatibility.
- omit_delegate_attrs: List[str] = []
A list of attribute names (strings) to not delegate to any other dictionary or object.
- property parent: qcodes.instrument.base.InstrumentBase
Returns the parent instrument. By default this is
None
. Any SubInstrument should subclass this to return the parent instrument.
- print_readable_snapshot(update: bool = False, max_chars: int = 80) None
Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.
- Parameters
update – If
True
, update the state by querying the instrument. IfFalse
, just use the latest values in memory. This argument gets passed to the snapshot function.max_chars – the maximum number of characters per line. The readable snapshot will be cropped if this value is exceeded. Defaults to 80 to be consistent with default terminal width.
- property root_instrument: qcodes.instrument.base.InstrumentBase
- set(param_name: str, value: Any) None
Shortcut for setting a parameter from its name and new value.
- Parameters
param_name – The name of a parameter of this instrument.
value – The new value to set.
- snapshot(update: Optional[bool] = False) Dict[Any, Any]
Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override
snapshot_base()
.- Parameters
update – Passed to snapshot_base.
- Returns
Base snapshot.
- snapshot_base(update: Optional[bool] = False, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]
State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class
qcodes.utils.helpers.NumpyJSONEncoder
supports).- Parameters
update – If
True
, update the state by querying the instrument. If None update the state if known to be invalid. IfFalse
, just use the latest values in memory and never update state.params_to_skip_update – List of parameter names that will be skipped in update even if update is True. This is useful if you have parameters that are slow to update but can be updated in a different way (as in the qdac). If you want to skip the update of certain parameters in all snapshots, use the
snapshot_get
attribute of those parameters instead.
- Returns
base snapshot
- Return type
- validate_status(verbose: bool = False) None
Validate the values of all gettable parameters
The validation is done for all parameters that have both a get and set method.
- Parameters
verbose – If
True
, then information about the parameters that are being check is printed.
- parameters: Dict[str, _BaseParameter] = {}
All the parameters supported by this instrument. Usually populated via
add_parameter()
.
- functions: Dict[str, Function] = {}
All the functions supported by this instrument. Usually populated via
add_function()
.
- submodules: Dict[str, Union['InstrumentModule', 'ChannelTuple']] = {}
All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via
add_submodule()
.
- instrument_modules: Dict[str, 'InstrumentModule'] = {}
All the instrument_modules of this instrument Usually populated via
add_submodule()
.