Stanford Research Systems Drivers

Classes:

SG384(name, address[, reset])	QCoDeS driver for the Stanford Research Systems SG384 RF Signal Generator.
SR560(name, **kwargs)	QCoDeS driver for the Stanford Research Systems SR560 Voltage-preamplifier.
SR830(name, address, **kwargs)	QCoDeS driver for the Stanford Research Systems SR830 Lock-in Amplifier.
SR860(name, address[, reset])	QCoDeS driver for the Stanford Research Systems SR860 Lock-in Amplifier.
SR865(name, address[, reset])	QCoDeS driver for the Stanford Research Systems SR865 Lock-in Amplifier.
SR865A(name, address[, reset])	QCoDeS driver for the Stanford Research Systems SR865A Lock-in Amplifier.
SR86xBuffer(parent, name)	Buffer module for the SR86x drivers.

class qcodes.instrument_drivers.stanford_research.SG384(name: str, address: str, reset: bool = False, **kwargs: Any)

Bases: VisaInstrument

QCoDeS driver for the Stanford Research Systems SG384 RF Signal Generator.

Status: beta version Includes the essential commands from the manual

Methods:

__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low-level interface to visa_handle.ask.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Disconnect and irreversibly tear down the instrument.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
device_clear()	Clear the buffers of the device
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
get_idn()	Parse a standard VISA *IDN? response into an ID dict.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
set_address(address)	Set the address for this instrument.
set_terminator(terminator)	Change the read terminator to use.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low-level interface to visa_handle.write.

Attributes:

ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
visa_handle	The VISA resource used by this instrument.
resource_manager	The VISA resource manager used by this instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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:

str

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

Disconnect and irreversibly tear down the instrument.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

device_clear() → None

Clear the buffers of the device

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

get_idn() → dict[str, str | None]

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[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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) → None

Change the read terminator to use.

Parameters:

terminator – Character(s) to look for at the end of a read and to end each write command with. eg. \r\n. If None the terminator will not be set.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = True, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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.

visabackend: str = visabackend

visa_handle: pyvisa.resources.MessageBasedResource = visa_handle

The VISA resource used by this instrument.

visalib: str | None = visalib

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

resource_manager = resource_manager

The VISA resource manager used by this instrument.

class qcodes.instrument_drivers.stanford_research.SR560(name: str, **kwargs: Any)

Bases: Instrument

QCoDeS driver for the Stanford Research Systems SR560 Voltage-preamplifier.

This is a virtual driver only and will not talk to your instrument.

Note:

• The cutoff_lo and cutoff_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.

Methods:

get_idn()	Parse a standard VISA *IDN? response into an ID dict.
__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low level method to write to the hardware and return a response.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Irreversibly stop this instrument and free its resources.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low level method to write a command string to the hardware.

Attributes:

ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

get_idn() → dict[str, str | None]

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.

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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 override ask.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

classmethod instances() → list[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = False, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).

Parameters:

• update – If True, update the state by querying the instrument. If None update the state if known to be invalid. If False, 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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 override write.

Parameters:

cmd – The string to send to the instrument.

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

class qcodes.instrument_drivers.stanford_research.SR830(name: str, address: str, **kwargs: Any)

Bases: VisaInstrument

QCoDeS driver for the Stanford Research Systems SR830 Lock-in Amplifier.

Attributes:

SNAP_PARAMETERS
ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
visa_handle	The VISA resource used by this instrument.
resource_manager	The VISA resource manager used by this instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

Methods:

snap(*parameters)	Get between 2 and 6 parameters at a single instant.
increment_sensitivity()	Increment the sensitivity setting of the lock-in.
decrement_sensitivity()	Decrement the sensitivity setting of the lock-in.
autorange([max_changes])	Automatically changes the sensitivity of the instrument according to the R value and defined max_changes.
set_sweep_parameters(sweep_param, start, stop)
__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low-level interface to visa_handle.ask.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Disconnect and irreversibly tear down the instrument.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
device_clear()	Clear the buffers of the device
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
get_idn()	Parse a standard VISA *IDN? response into an ID dict.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
set_address(address)	Set the address for this instrument.
set_terminator(terminator)	Change the read terminator to use.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low-level interface to visa_handle.write.

SNAP_PARAMETERS: ClassVar[dict[str, str]] = {'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, ...]

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

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

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

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: Parameter, start: float, stop: float, n_points: int = 10, label: str | None = None) → None

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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:

str

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

Disconnect and irreversibly tear down the instrument.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

device_clear() → None

Clear the buffers of the device

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

get_idn() → dict[str, str | None]

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[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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) → None

Change the read terminator to use.

Parameters:

terminator – Character(s) to look for at the end of a read and to end each write command with. eg. \r\n. If None the terminator will not be set.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = True, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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.

visabackend: str = visabackend

visa_handle: pyvisa.resources.MessageBasedResource = visa_handle

The VISA resource used by this instrument.

visalib: str | None = visalib

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

resource_manager = resource_manager

The VISA resource manager used by this instrument.

class qcodes.instrument_drivers.stanford_research.SR860(name: str, address: str, reset: bool = False, **kwargs: str)

Bases: SR86x

QCoDeS driver for the Stanford Research Systems SR860 Lock-in Amplifier.

The SR860 instrument is almost equal to the SR865, except for the max frequency

Attributes:

PARAMETER_NAMES
ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
visa_handle	The VISA resource used by this instrument.
resource_manager	The VISA resource manager used by this instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

Methods:

__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low-level interface to visa_handle.ask.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Disconnect and irreversibly tear down the instrument.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
device_clear()	Clear the buffers of the device
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
get_data_channels_dict([requery_names])	Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
get_data_channels_parameters([query_instrument])	Convenience method to query a list of parameters which the data channels are currently assigned to.
get_data_channels_values()	Queries the current values of the data channels
get_idn()	Parse a standard VISA *IDN? response into an ID dict.
get_values(*parameter_names)	Get values of 2 or 3 parameters that are measured by the lock-in amplifier.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
set_address(address)	Set the address for this instrument.
set_terminator(terminator)	Change the read terminator to use.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low-level interface to visa_handle.write.

PARAMETER_NAMES: ClassVar[dict[str, str]] = {'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'}

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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:

str

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

Disconnect and irreversibly tear down the instrument.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

device_clear() → None

Clear the buffers of the device

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

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, str | None]

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[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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) → None

Change the read terminator to use.

Parameters:

terminator – Character(s) to look for at the end of a read and to end each write command with. eg. \r\n. If None the terminator will not be set.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = True, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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.

visabackend: str = visabackend

visa_handle: pyvisa.resources.MessageBasedResource = visa_handle

The VISA resource used by this instrument.

visalib: str | None = visalib

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

resource_manager = resource_manager

The VISA resource manager used by this instrument.

class qcodes.instrument_drivers.stanford_research.SR865(name: str, address: str, reset: bool = False, **kwargs: str)

Bases: SR86x

QCoDeS driver for the Stanford Research Systems SR865 Lock-in Amplifier.

The SR865 instrument is almost equal to the SR860, except for the max frequency

Attributes:

PARAMETER_NAMES
ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
visa_handle	The VISA resource used by this instrument.
resource_manager	The VISA resource manager used by this instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

Methods:

__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low-level interface to visa_handle.ask.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Disconnect and irreversibly tear down the instrument.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
device_clear()	Clear the buffers of the device
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
get_data_channels_dict([requery_names])	Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
get_data_channels_parameters([query_instrument])	Convenience method to query a list of parameters which the data channels are currently assigned to.
get_data_channels_values()	Queries the current values of the data channels
get_idn()	Parse a standard VISA *IDN? response into an ID dict.
get_values(*parameter_names)	Get values of 2 or 3 parameters that are measured by the lock-in amplifier.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
set_address(address)	Set the address for this instrument.
set_terminator(terminator)	Change the read terminator to use.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low-level interface to visa_handle.write.

PARAMETER_NAMES: ClassVar[dict[str, str]] = {'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'}

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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:

str

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

Disconnect and irreversibly tear down the instrument.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

device_clear() → None

Clear the buffers of the device

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

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, str | None]

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[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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) → None

Change the read terminator to use.

Parameters:

terminator – Character(s) to look for at the end of a read and to end each write command with. eg. \r\n. If None the terminator will not be set.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = True, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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.

visabackend: str = visabackend

visa_handle: pyvisa.resources.MessageBasedResource = visa_handle

The VISA resource used by this instrument.

visalib: str | None = visalib

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

resource_manager = resource_manager

The VISA resource manager used by this instrument.

class qcodes.instrument_drivers.stanford_research.SR865A(name: str, address: str, reset: bool = False, **kwargs: str)

Bases: SR86x

QCoDeS driver for the Stanford Research Systems SR865A Lock-in Amplifier.

The SR865A instrument is almost equal to the SR865, except for the max frequency

Attributes:

PARAMETER_NAMES
ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
visa_handle	The VISA resource used by this instrument.
resource_manager	The VISA resource manager used by this instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

Methods:

__del__()	Close the instrument and remove its instance record.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Simplified repr giving just the class and name.
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)	Write a command string to the hardware and return a response.
ask_raw(cmd)	Low-level interface to visa_handle.ask.
call(func_name, *args)	Shortcut for calling a function from its name.
close()	Disconnect and irreversibly tear down the instrument.
close_all()	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.
connect_message([idn_param, begin_time])	Print a standard message on initial connection to an instrument.
device_clear()	Clear the buffers of the device
exist(name[, instrument_class])	Check if an instrument with a given names exists (i.e. is already instantiated).
find_instrument(name[, instrument_class])	Find an existing instrument by name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
get_data_channels_dict([requery_names])	Returns a dictionary where the keys are parameter names currently assigned to the data channels, and values are the values of those parameters.
get_data_channels_parameters([query_instrument])	Convenience method to query a list of parameters which the data channels are currently assigned to.
get_data_channels_values()	Queries the current values of the data channels
get_idn()	Parse a standard VISA *IDN? response into an ID dict.
get_values(*parameter_names)	Get values of 2 or 3 parameters that are measured by the lock-in amplifier.
instances()	Get all currently defined instances of this instrument class.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
is_valid(instr_instance)	Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a "valid" instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
record_instance(instance)	Record (a weak ref to) an instance in a class's instance list.
remove_instance(instance)	Remove a particular instance from the record.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
set_address(address)	Set the address for this instrument.
set_terminator(terminator)	Change the read terminator to use.
snapshot([update])	Decorate a snapshot dictionary with metadata.
snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)	Write a command string with NO response to the hardware.
write_raw(cmd)	Low-level interface to visa_handle.write.

PARAMETER_NAMES: ClassVar[dict[str, str]] = {'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'}

__del__() → None

Close the instrument and remove its instance record.

__getitem__(key: str) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Simplified repr giving just the class and 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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent 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 call super().ask(new_cmd). Subclasses that define a new hardware communication should instead override ask_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:

str

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

Disconnect and irreversibly tear down the instrument.

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: float | None = 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 is self._t0, set at start of Instrument.__init__.

delegate_attr_dicts: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

device_clear() → None

Clear the buffers of the device

static exist(name: str, instrument_class: type[Instrument] | None = 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: type[T] | None = None) → T | Instrument

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:

• KeyError – If no instrument of that name was found, or if its reference is invalid (dead).

• TypeError – If a specific class was requested but a different type was found.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

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, str | None]

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[T]

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: 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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase | None

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. If False, 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: 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: Instrument) → None

Remove a particular instance from the record.

Parameters:

instance – The instance to remove

property root_instrument: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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) → None

Change the read terminator to use.

Parameters:

terminator – Character(s) to look for at the end of a read and to end each write command with. eg. \r\n. If None the terminator will not be set.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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: bool | None = True, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class 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:

dict

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 call super().write(new_cmd). Subclasses that define a new hardware communication should instead override write_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.

visabackend: str = visabackend

visa_handle: pyvisa.resources.MessageBasedResource = visa_handle

The VISA resource used by this instrument.

visalib: str | None = visalib

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}

resource_manager = resource_manager

The VISA resource manager used by this instrument.

class qcodes.instrument_drivers.stanford_research.SR86xBuffer(parent: SR86x, name: str)

Bases: InstrumentChannel

Buffer module for the SR86x drivers.

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

Methods:

snapshot_base([update, params_to_skip_update])	State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).
set_capture_rate_to_maximum()	Sets the capture rate to maximum.
start_capture(acquisition_mode, trigger_mode)	Start an acquisition.
stop_capture()	Stop a capture
set_capture_length_to_fit_samples(sample_count)	Set the capture length of the buffer to fit the given number of samples.
wait_until_samples_captured(sample_count)	Wait until the given number of samples is captured.
get_capture_data(sample_count)	Read the given number of samples of the capture data from the buffer.
capture_one_sample_per_trigger(...)	Capture one sample per each trigger, and return when the specified number of triggers has been received.
capture_samples_after_trigger(sample_count, ...)	Capture a number of samples after a trigger has been received.
capture_samples(sample_count)	Capture a number of samples at a capture rate, starting immediately.
__getitem__(key)	Delegate instrument['name'] to parameter or function 'name'.
__getstate__()	Prevent pickling instruments, and give a nice error message.
__repr__()	Custom repr to give parent information
add_function(name, **kwargs)	Bind one Function to this instrument.
add_parameter(name[, parameter_class])	Bind one Parameter to this instrument.
add_submodule(name, submodule)	Bind one submodule to this instrument.
ask(cmd)
ask_raw(cmd)
call(func_name, *args)	Shortcut for calling a function from its name.
get(param_name)	Shortcut for getting a parameter from its name.
get_component(full_name)	Recursively get a component of the instrument by full_name.
invalidate_cache()	Invalidate the cache of all parameters on the instrument.
load_metadata(metadata)	Load metadata into this classes metadata dictionary.
print_readable_snapshot([update, max_chars])	Prints a readable version of the snapshot.
set(param_name, value)	Shortcut for setting a parameter from its name and new value.
snapshot([update])	Decorate a snapshot dictionary with metadata.
validate_status([verbose])	Validate the values of all gettable parameters
write(cmd)
write_raw(cmd)

Attributes:

ancestors	Ancestors in the form of a list of InstrumentBase
delegate_attr_dicts	A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.
delegate_attr_objects	A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.
full_name	Full name of the instrument.
label	Nicely formatted label of the instrument.
name	Full name of the instrument
name_parts	A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.
omit_delegate_attrs	A list of attribute names (strings) to not delegate to any other dictionary or object.
parent	The parent instrument.
root_instrument	The topmost parent of this module.
short_name	Short name of the instrument.
parameters	All the parameters supported by this instrument.
functions	All the functions supported by this instrument.
submodules	All the submodules of this instrument such as channel lists or logical groupings of parameters.
instrument_modules	All the InstrumentModule of this instrument Usually populated via add_submodule().

snapshot_base(update: bool | None = False, params_to_skip_update: Sequence[str] | None = None) → dict[Any, Any]

State of the instrument as a JSON-compatible dict (everything that the custom JSON encoder class NumpyJSONEncoder supports).

Parameters:

• update – If True, update the state by querying the instrument. If None update the state if known to be invalid. If False, 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:

dict

set_capture_rate_to_maximum() → None

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

Start an acquisition. Please see page 137 of the manual for a detailed explanation.

Parameters:

• acquisition_mode – “ONE” | “CONT”

• trigger_mode – “IMM” | “TRIG” | “SAMP”

stop_capture() → None

Stop a capture

set_capture_length_to_fit_samples(sample_count: int) → None

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

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, ndarray]

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, ndarray]

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, ndarray]

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, ndarray]

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) → Callable[[...], Any] | Parameter

Delegate instrument[‘name’] to parameter or function ‘name’.

__getstate__() → None

Prevent pickling instruments, and give a nice error message.

__repr__() → str

Custom repr to give parent information

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.

Note

We do not recommend the usage of Function for any new driver. Function does not add any significant features over a method defined on the class.

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[ParameterBase] | None = None, **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 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 parameters.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: 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 a ChannelTuple.

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:

• KeyError – If this instrument already contains a submodule with this name.

• TypeError – If the submodule that we are trying to add is not an instance of an Metadatable object.

property ancestors: tuple[InstrumentBase, ...]

Ancestors in the form of a list of InstrumentBase

The list starts with the current module then the parent and the parents parent until the root instrument is reached.

ask(cmd: str) → str

ask_raw(cmd: str) → str

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: ClassVar[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 of self.

delegate_attr_objects: ClassVar[list[str]] = []

A list of names (strings) of objects which are (or will be) attributes of self, whose attributes should be passed through to self.

property full_name: str

Full name of the instrument.

For an InstrumentModule this includes all parents separated by _

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_component(full_name: str) → MetadatableWithName

Recursively get a component of the instrument by full_name.

Parameters:

name – The name of the component to get.

Returns:

The component with the given name.

Raises:

KeyError – If the component does not exist.

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.

property label: str

Nicely formatted label of the instrument.

load_metadata(metadata: Mapping[str, Any]) → None

Load metadata into this classes metadata dictionary.

Parameters:

metadata – Metadata to load.

property name: str

Full name of the instrument

This is equivalent to full_name() for backwards compatibility.

property name_parts: list[str]

A list of all the parts of the instrument name from root_instrument() to the current InstrumentModule.

omit_delegate_attrs: ClassVar[list[str]] = []

A list of attribute names (strings) to not delegate to any other dictionary or object.

property parent: InstrumentBase

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. If False, 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: InstrumentBase

The topmost parent of this module.

For the root_instrument this is self.

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.

property short_name: str

Short name of the instrument.

For an InstrumentModule this does not include any parent names.

snapshot(update: bool | None = False) → dict[str, 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.

write(cmd: str) → None

write_raw(cmd: str) → None

parameters: dict[str, ParameterBase] = {}

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, 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 InstrumentModule of this instrument Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)

metadata: dict[str, Any] = {}