qcodes.instrument_drivers.QDev package

Submodules

qcodes.instrument_drivers.QDev.QDac_channels module

class qcodes.instrument_drivers.QDev.QDac_channels.QDac(name: str, address: str, num_chans: int = 48, update_currents: bool = True, **kwargs: Any)[source]

Bases: qcodes.instrument.visa.VisaInstrument

Channelised driver for the QDev digital-analog converter QDac

Based on “DAC_commands_v_13.pdf” Tested with Software Version: 0.170202

The driver assumes that the instrument is ALWAYS in verbose mode OFF

Instantiates the instrument.

Parameters
  • name – The instrument name used by qcodes

  • address – The VISA name of the resource

  • num_chans – Number of channels to assign. Default: 48

  • update_currents – Whether to query all channels for their current current value on startup. Default: True.

Returns

QDac object

max_status_age = 1
snapshot_base(update: Optional[bool] = False, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any][source]

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

Parameters
  • update – If True, update the state by querying the instrument. If None 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

printslopes() None[source]

Print the finite slopes assigned to channels

write(cmd: str) None[source]

QDac always returns something even from set commands, even when verbose mode is off, so we’ll override write to take this out if you want to use this response, we put it in self._write_response (but only for the very last write call)

In this method we expect to read one termination char per command. As commands are concatenated by ; we count the number of concatenated commands as count(‘;’) + 1 e.g. ‘wav 1 1 1 0;fun 2 1 100 1 1’ is two commands. Note that only the response of the last command will be available in _write_response

read() str[source]
connect_message(idn_part: str = 'IDN', being_time: Optional[float] = None) None[source]

Override of the standard Instrument class connect_message. Usually, the response to *IDN? is printed. Here, the software version is printed.

print_overview(update_currents: bool = False) None[source]

Pretty-prints the status of the QDac

__del__() None

Close the instrument and remove its instance record.

__getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.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. If your case is more complicated, you’re probably better off simply making a new method in your Instrument subclass definition.

Parameters
  • name – How the Function will be stored within instrument.Functions and also how you address it using the shortcut methods: instrument.call(func_name, *args) etc.

  • **kwargs – constructor kwargs for Function

Raises

KeyError – If this instrument already has a function with this name.

add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None

Bind one Parameter to this instrument.

Instrument subclasses can call this repeatedly in their __init__ for every real parameter of the instrument.

In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.

Parameters
  • name – How the parameter will be stored within instrument.parameters and also how you address it using the shortcut methods: instrument.set(param_name, value) etc.

  • parameter_class – You can construct the parameter out of any class. Default parameter.Parameter.

  • **kwargs – Constructor arguments for parameter_class.

Raises
  • KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.

  • ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.

add_submodule(name: str, submodule: Union[InstrumentBase, ChannelList]) 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.

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: List[qcodes.instrument.base.InstrumentBase]

Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.

ask(cmd: str) str

Write a command string to the hardware and return a response.

Subclasses that transform cmd should override this method, and in it 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.

check_error(ret_code: int) None

Default error checking, raises an error if return code !=0. Does not differentiate between warnings or specific error messages. Override this function in your driver if you want to add specific error messages.

Parameters

ret_code – A Visa error code. See eg: https://github.com/hgrecco/pyvisa/blob/master/pyvisa/errors.py

Raises

visa.VisaIOError – if ret_code indicates a communication problem.

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())
delegate_attr_dicts: List[str] = ['parameters', 'functions', 'submodules']

A list of names (strings) of dictionaries which are (or will be) attributes of self, whose keys should be treated as attributes of self.

delegate_attr_objects: List[str] = []

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

device_clear() None

Clear the buffers of the device

static exist(name: str, instrument_class: Optional[type] = None) bool

Check if an instrument with a given names exists (i.e. is already instantiated).

Parameters
  • name – Name of the instrument.

  • instrument_class – The type of instrument you are looking for.

classmethod find_instrument(name: str, instrument_class: Optional[type] = None) qcodes.instrument.base.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
get(param_name: str) Any

Shortcut for getting a parameter from its name.

Parameters

param_name – The name of a parameter of this instrument.

Returns

The current value of the parameter.

get_idn() Dict[str, Optional[str]]

Parse a standard VISA *IDN? response into an ID dict.

Even though this is the VISA standard, it applies to various other types as well, such as IPInstruments, so it is included here in the Instrument base class.

Override this if your instrument does not support *IDN? or returns a nonstandard IDN string. This string is supposed to be a comma-separated list of vendor, model, serial, and firmware, but semicolon and colon are also common separators so we accept them here as well.

Returns

A dict containing vendor, model, serial, and firmware.

classmethod instances() List[qcodes.instrument.base.Instrument]

Get all currently defined instances of this instrument class.

You can use this to get the objects back if you lose track of them, and it’s also used by the test system to find objects to test against.

Returns

A list of instances.

static is_valid(instr_instance: qcodes.instrument.base.Instrument) bool

Check if a given instance of an instrument is valid: if an instrument has been closed, its instance is not longer a “valid” instrument.

Parameters

instr_instance – Instance of an Instrument class or its subclass.

load_metadata(metadata: Dict[Any, Any]) None

Load metadata into this classes metadata dictionary.

Parameters

metadata – Metadata to load.

property name: str

Name of the instrument

property name_parts: List[str]
omit_delegate_attrs: List[str] = []

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

property parent: Optional[qcodes.instrument.base.InstrumentBase]

Returns the parent instrument. By default this is None. Any SubInstrument should subclass this to return the parent instrument.

print_readable_snapshot(update: bool = False, max_chars: int = 80) None

Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.

Parameters
  • update – If True, update the state by querying the instrument. 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: qcodes.instrument.base.Instrument) None

Record (a weak ref to) an instance in a class’s instance list.

Also records the instance in list of all instruments, and verifies that there are no other instruments with the same name.

Parameters

instance – Instance to record.

Raises

KeyError – If another instance with the same name is already present.

classmethod remove_instance(instance: qcodes.instrument.base.Instrument) None

Remove a particular instance from the record.

Parameters

instance – The instance to remove

property root_instrument: qcodes.instrument.base.InstrumentBase
set(param_name: str, value: Any) None

Shortcut for setting a parameter from its name and new value.

Parameters
  • param_name – The name of a parameter of this instrument.

  • value – The new value to set.

set_address(address: str) None

Set the address for this instrument.

Parameters

address – The visa resource name to use to connect. The address should be the actual address and just that. If you wish to change the backend for VISA, use the self.visalib attribute (and then call this function).

set_terminator(terminator: str) None

Change the read terminator to use.

Parameters

terminator – Character(s) to look for at the end of a read. eg. \r\n.

shared_kwargs = ()
property short_name: str

Short name of the instrument

snapshot(update: Optional[bool] = False) Dict[Any, Any]

Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override snapshot_base().

Parameters

update – Passed to snapshot_base.

Returns

Base snapshot.

validate_status(verbose: bool = False) None

Validate the values of all gettable parameters

The validation is done for all parameters that have both a get and set method.

Parameters

verbose – If True, then information about the parameters that are being check is printed.

write_raw(cmd: str) None

Low-level interface to visa_handle.write.

Parameters

cmd – The command to send to the instrument.

parameters: Dict[str, _BaseParameter] = {}

All the parameters supported by this instrument. Usually populated via add_parameter().

functions: Dict[str, Function] = {}

All the functions supported by this instrument. Usually populated via add_function().

submodules: Dict[str, Union['InstrumentBase', 'ChannelList']] = {}

All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via add_submodule().

log: InstrumentLoggerAdapter = get_instrument_logger(self, __name__)
class qcodes.instrument_drivers.QDev.QDac_channels.QDacChannel(parent: qcodes.instrument.base.Instrument, name: str, channum: int)[source]

Bases: qcodes.instrument.channel.InstrumentChannel

A single output channel of the QDac.

Exposes chan.v, chan.vrange, chan.slope, chan.i, chan.irange

Parameters
  • parent – The instrument to which the channel is attached.

  • name – The name of the channel

  • channum – The number of the channel in question (1-48)

snapshot_base(update: Optional[bool] = False, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any][source]

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

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

__getitem__(key: str) Union[Callable[[...], Any], qcodes.instrument.parameter.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. If your case is more complicated, you’re probably better off simply making a new method in your Instrument subclass definition.

Parameters
  • name – How the Function will be stored within instrument.Functions and also how you address it using the shortcut methods: instrument.call(func_name, *args) etc.

  • **kwargs – constructor kwargs for Function

Raises

KeyError – If this instrument already has a function with this name.

add_parameter(name: str, parameter_class: type = <class 'qcodes.instrument.parameter.Parameter'>, **kwargs: Any) None

Bind one Parameter to this instrument.

Instrument subclasses can call this repeatedly in their __init__ for every real parameter of the instrument.

In this sense, parameters are the state variables of the instrument, anything the user can set and/or get.

Parameters
  • name – How the parameter will be stored within instrument.parameters and also how you address it using the shortcut methods: instrument.set(param_name, value) etc.

  • parameter_class – You can construct the parameter out of any class. Default parameter.Parameter.

  • **kwargs – Constructor arguments for parameter_class.

Raises
  • KeyError – If this instrument already has a parameter with this name and the parameter being replaced is not an abstract parameter.

  • ValueError – If there is an existing abstract parameter and the unit of the new parameter is inconsistent with the existing one.

add_submodule(name: str, submodule: Union[InstrumentBase, ChannelList]) 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.

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: List[qcodes.instrument.base.InstrumentBase]

Returns a list of instruments, starting from the current instrument and following to the parent instrument and the parents parent instrument until the root instrument is reached.

ask(cmd: str) str
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: 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: 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
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.

load_metadata(metadata: Dict[Any, Any]) None

Load metadata into this classes metadata dictionary.

Parameters

metadata – Metadata to load.

property name: str

Name of the instrument

property name_parts: List[str]
omit_delegate_attrs: List[str] = []

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

property parent: qcodes.instrument.base.InstrumentBase

Returns the parent instrument. By default this is None. Any SubInstrument should subclass this to return the parent instrument.

print_readable_snapshot(update: bool = False, max_chars: int = 80) None

Prints a readable version of the snapshot. The readable snapshot includes the name, value and unit of each parameter. A convenience function to quickly get an overview of the status of an instrument.

Parameters
  • update – If True, update the state by querying the instrument. 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: qcodes.instrument.base.InstrumentBase
set(param_name: str, value: Any) None

Shortcut for setting a parameter from its name and new value.

Parameters
  • param_name – The name of a parameter of this instrument.

  • value – The new value to set.

property short_name: str

Short name of the instrument

snapshot(update: Optional[bool] = False) Dict[Any, Any]

Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override snapshot_base().

Parameters

update – Passed to snapshot_base.

Returns

Base snapshot.

validate_status(verbose: bool = False) None

Validate the values of all gettable parameters

The validation is done for all parameters that have both a get and set method.

Parameters

verbose – If True, then information about the parameters that are being check is printed.

write(cmd: str) None
write_raw(cmd: str) None
parameters: Dict[str, _BaseParameter] = {}

All the parameters supported by this instrument. Usually populated via add_parameter().

functions: Dict[str, Function] = {}

All the functions supported by this instrument. Usually populated via add_function().

submodules: Dict[str, Union['InstrumentBase', 'ChannelList']] = {}

All the submodules of this instrument such as channel lists or logical groupings of parameters. Usually populated via add_submodule().

class qcodes.instrument_drivers.QDev.QDac_channels.QDacMultiChannelParameter(channels: Sequence[qcodes.instrument.channel.InstrumentChannel], param_name: str, *args: Any, **kwargs: Any)[source]

Bases: qcodes.instrument.channel.MultiChannelInstrumentParameter

The class to be returned by __getattr__ of the ChannelList. Here customised for fast multi-readout of voltages.

get_raw() Tuple[Any, ...][source]

Return a tuple containing the data from each of the channels in the list.

__str__() str

Include the instrument name with the Parameter name if possible.

property abstract: Optional[bool]
property full_name: str

Name of the parameter including the name of the instrument and submodule that the parameter may be bound to. The names are separated by underscores, like this: instrument_submodule_parameter.

property full_names: Tuple[str, ...]

Overwrite full_names because the instrument name is already included in the name. This happens because the instrument name is included in the channel name merged into the parameter name above.

get_ramp_values(value: Union[float, Sized], step: Optional[float] = None) Sequence[Union[float, Sized]]

Return values to sweep from current value to target value. This method can be overridden to have a custom sweep behaviour. It can even be overridden by a generator.

Parameters
  • value – target value

  • step – maximum step size

Returns

List of stepped values, including target value.

property gettable: bool

Is it allowed to call get on this parameter?

property instrument: Optional[InstrumentBase]

Return the first instrument that this parameter is bound to. E.g if this is bound to a channel it will return the channel and not the instrument that the channel is bound too. Use root_instrument() to get the real instrument.

property inter_delay: float

Delay time between consecutive set operations. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.

Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay between sets.

Getter

Returns the current inter_delay.

Setter

Sets the value of the inter_delay.

Raises
load_metadata(metadata: Dict[Any, Any]) None

Load metadata into this classes metadata dictionary.

Parameters

metadata – Metadata to load.

property name: str

Name of the parameter. This is identical to short_name().

property name_parts: List[str]

List of the parts that make up the full name of this parameter

property post_delay: float

Delay time after start of set operation, for each set. The actual time will not be shorter than this, but may be longer if the underlying set call takes longer.

Typically used in conjunction with step to create an effective ramp rate, but can also be used without a step to enforce a delay after every set. One might think of post_delay as how long a set operation is supposed to take. For example, there might be an instrument that needs extra time after setting a parameter although the command for setting the parameter returns quickly.

Getter

Returns the current post_delay.

Setter

Sets the value of the post_delay.

Raises
property raw_value: Any

Note that this property will be deprecated soon. Use cache.raw_value instead.

Represents the cached raw value of the parameter.

Getter

Returns the cached raw value of the parameter.

restore_at_exit(allow_changes: bool = True) qcodes.instrument.parameter._SetParamContext

Use a context manager to restore the value of a parameter after a with block.

By default, the parameter value may be changed inside the block, but this can be prevented with allow_changes=False. This can be useful, for example, for debugging a complex measurement that unintentionally modifies a parameter.

Example

>>> p = Parameter("p", set_cmd=None, get_cmd=None)
>>> p.set(2)
>>> with p.restore_at_exit():
...     p.set(3)
...     print(f"value inside with block: {p.get()}")  # prints 3
>>> print(f"value after with block: {p.get()}")  # prints 2
>>> with p.restore_at_exit(allow_changes=False):
...     p.set(5)  # raises an exception
property root_instrument: Optional[InstrumentBase]

Return the fundamental instrument that this parameter belongs too. E.g if the parameter is bound to a channel this will return the fundamental instrument that that channel belongs to. Use instrument() to get the channel.

set_raw(value: Any) None

Set all parameters to this value.

Parameters

value – The value to set to. The type is given by the underlying parameter.

set_to(value: Any, allow_changes: bool = False) qcodes.instrument.parameter._SetParamContext

Use a context manager to temporarily set a parameter to a value. By default, the parameter value cannot be changed inside the context. This may be overridden with allow_changes=True.

Examples

>>> from qcodes import Parameter
>>> p = Parameter("p", set_cmd=None, get_cmd=None)
>>> p.set(2)
>>> with p.set_to(3):
...     print(f"p value in with block {p.get()}")  # prints 3
...     p.set(5)  # raises an exception
>>> print(f"p value outside with block {p.get()}")  # prints 2
>>> with p.set_to(3, allow_changes=True):
...     p.set(5)  # now this works
>>> print(f"value after second block: {p.get()}")  # still prints 2
property setpoint_full_names: Optional[Sequence[Sequence[str]]]

Full names of setpoints including instrument names, if available

property settable: bool

Is it allowed to call set on this parameter?

property short_name: str

Short name of the parameter. This is without the name of the instrument or submodule that the parameter may be bound to. For full name refer to full_name().

property short_names: Tuple[str, ...]

short_names is identical to names i.e. the names of the parameter parts but does not add the instrument name.

It exists for consistency with instruments and other parameters.

snapshot(update: Optional[bool] = False) Dict[Any, Any]

Decorate a snapshot dictionary with metadata. DO NOT override this method if you want metadata in the snapshot instead, override snapshot_base().

Parameters

update – Passed to snapshot_base.

Returns

Base snapshot.

snapshot_base(update: Optional[bool] = True, params_to_skip_update: Optional[Sequence[str]] = None) Dict[Any, Any]

State of the parameter as a JSON-compatible dict (everything that the custom JSON encoder class qcodes.utils.helpers.NumpyJSONEncoder supports).

If the parameter has been initiated with snapshot_value=False, the snapshot will NOT include the value and raw_value of the parameter.

Parameters
  • update – If True, update the state by calling parameter.get() unless snapshot_get of the parameter is False. If update is None, use the current value from the cache unless the cache is invalid. If False, never call parameter.get().

  • params_to_skip_update – No effect but may be passed from superclass

Returns

base snapshot

property snapshot_value: bool

If True the value of the parameter will be included in the snapshot.

property step: Optional[float]

Stepsize that this Parameter uses during set operation. Stepsize must be a positive number or None. If step is a positive number, this is the maximum value change allowed in one hardware call, so a single set can result in many calls to the hardware if the starting value is far from the target. All but the final change will attempt to change by +/- step exactly. If step is None stepping will not be used.

Getter

Returns the current stepsize.

Setter

Sets the value of the step.

Raises
  • TypeError – if step is set to not numeric or None

  • ValueError – if step is set to negative

  • TypeError – if step is set to not integer or None for an integer parameter

  • TypeError – if step is set to not a number on None

property underlying_instrument: Optional[InstrumentBase]

Returns an instance of the underlying hardware instrument that this parameter communicates with, per this parameter’s implementation.

This is useful in the case where a parameter does not belongs to an instrument instance that represents a real hardware instrument but actually uses a real hardware instrument in its implementation (e.g. via calls to one or more parameters of that real hardware instrument). This is also useful when a parameter does belong to an instrument instance but that instance does not represent the real hardware instrument that the parameter interacts with: hence root_instrument of the parameter cannot be the hardware_instrument, however underlying_instrument can be implemented to return the hardware_instrument.

By default it returns the root_instrument of the parameter.

validate(value: Any) None

Validate the value supplied.

Parameters

value – value to validate

Raises
  • TypeError – If the value is of the wrong type.

  • ValueError – If the value is outside the bounds specified by the validator.

Module contents