# Generic SCPI Instruments¶

## SCPIInstrument - Base class for instruments using the SCPI protocol¶

class instruments.generic_scpi.SCPIInstrument(filelike)[source]

Base class for all SCPI-compliant instruments. Inherits from from Instrument.

This class does not implement any instrument-specific communication commands. What it does add is several of the generic SCPI star commands. This includes commands such as *IDN?, *OPC?, and *RST.

Example usage:

>>> import instruments as ik
>>> inst = ik.generic_scpi.SCPIInstrument.open_tcpip('192.168.0.2', 8888)
>>> print(inst.name)

class ErrorCodes[source]

Enumeration describing error codes as defined by SCPI 1999.0. Error codes that are equal to 0 mod 100 are defined to be generic.

block_data_error = -160
block_data_not_allowed = -168
character_data_error = -140
character_data_not_allowed = -148
character_data_too_long = -144
command_error = -100
command_header_error = -110
data_type_error = -104
exponent_too_large = -123
expression_error = -170
expression_not_allowed = -178
get_not_allowed = -105
header_separator_error = -111
header_suffix_out_of_range = -114
invalid_block_data = -161
invalid_character = -101
invalid_character_data = -141
invalid_character_in_number = -121
invalid_expression = -171
invalid_inside_macro_definition = -183
invalid_outside_macro_definition = -181
invalid_separator = -103
invalid_string_data = -151
invalid_suffix = -131
macro_error = -180
macro_parameter_error = -184
missing_parameter = -109
no_error = 0
numeric_data_error = -120
numeric_data_not_allowed = -128
operation_complete = -800
parameter_not_allowed = -108
power_on = -500

Raised when the instrument detects that it has been turned from off to on.

program_mnemonic_too_long = -112
request_control_event = -700
string_data_error = -150
string_data_not_allowed = -158
suffix_error = -130
suffix_not_allowed = -138
suffix_too_long = -134
syntax_error = -102
too_many_digits = -124
undefined_header = -113
unexpected_number_of_parameters = -115
user_request_event = -600
check_error_queue()[source]

Checks and clears the error queue for this device, returning a list of SCPIInstrument.ErrorCodes or int elements for each error reported by the connected instrument.

clear()[source]

Clear instrument. Consult manual for specifics related to that instrument.

reset()[source]

Reset instrument. On many instruments this is a factory reset and will revert all settings to default.

trigger()[source]

Send a software trigger event to the instrument. On most instruments this will cause some sort of hardware event to start. For example, a multimeter might take a measurement.

This software trigger usually performs the same action as a hardware trigger to your instrument.

wait_to_continue()[source]

Instruct the instrument to wait until it has completed all received commands before continuing.

display_brightness

Brightness of the display on the connected instrument, represented as a float ranging from 0 (dark) to 1 (full brightness).

Type: float
display_contrast

Contrast of the display on the connected instrument, represented as a float ranging from 0 (no contrast) to 1 (full contrast).

Type: float
line_frequency

Gets/sets the power line frequency setting for the instrument.

Returns: The power line frequency Hertz Quantity
name

The name of the connected instrument, as reported by the standard SCPI command *IDN?.

Return type: str
op_complete

Check if all operations sent to the instrument have been completed.

Return type: bool
power_on_status

Gets/sets the power on status for the instrument.

Type: bool
scpi_version

Returns the version of the SCPI protocol supported by this instrument, as specified by the SYST:VERS? command described in section 21.21 of the SCPI 1999 standard.

self_test_ok

Gets the results of the instrument’s self test. This lets you check if the self test was sucessful or not.

Return type: bool

## SCPIMultimeter - Generic multimeter using SCPI commands¶

class instruments.generic_scpi.SCPIMultimeter(filelike)[source]

This class is used for communicating with generic SCPI-compliant multimeters.

Example usage:

>>> import instruments as ik
>>> inst = ik.generic_scpi.SCPIMultimeter.open_tcpip("192.168.1.1")
>>> print(inst.measure(inst.Mode.resistance))

class InputRange[source]

Valid device range parameters outside of directly specifying the range.

automatic = 'AUTO'
default = 'DEF'
maximum = 'MAX'
minimum = 'MIN'
class Mode[source]

Enum of valid measurement modes for (most) SCPI compliant multimeters

capacitance = 'CAP'
continuity = 'CONT'
current_ac = 'CURR:AC'
current_dc = 'CURR:DC'
diode = 'DIOD'
fourpt_resistance = 'FRES'
frequency = 'FREQ'
period = 'PER'
resistance = 'RES'
temperature = 'TEMP'
voltage_ac = 'VOLT:AC'
voltage_dc = 'VOLT:DC'
class Resolution[source]

Valid measurement resolution parameters outside of directly the resolution.

default = 'DEF'
maximum = 'MAX'
minimum = 'MIN'
class SampleCount[source]

Valid sample count parameters outside of directly the value.

default = 'DEF'
maximum = 'MAX'
minimum = 'MIN'
class SampleSource[source]

Valid sample source parameters.

1. “immediate”: The trigger delay time is inserted between successive
samples. After the first measurement is completed, the instrument waits the time specified by the trigger delay and then performs the next sample.
2. “timer”: Successive samples start one sample interval after the
START of the previous sample.
immediate = 'IMM'
timer = 'TIM'
class TriggerCount[source]

Valid trigger count parameters outside of directly the value.

default = 'DEF'
infinity = 'INF'
maximum = 'MAX'
minimum = 'MIN'
class TriggerMode[source]

Valid trigger sources for most SCPI Multimeters.

“Immediate”: This is a continuous trigger. This means the trigger signal is always present.

“External”: External TTL pulse on the back of the instrument. It is active low.

“Bus”: Causes the instrument to trigger when a *TRG command is sent by software. This means calling the trigger() function.

bus = 'BUS'
external = 'EXT'
immediate = 'IMM'
measure(mode=None)[source]

Instruct the multimeter to perform a one time measurement. The instrument will use default parameters for the requested measurement. The measurement will immediately take place, and the results are directly sent to the instrument’s output buffer.

Method returns a Python quantity consisting of a numpy array with the instrument value and appropriate units. If no appropriate units exist, (for example, continuity), then return type is float.

Parameters: mode (Mode) – Desired measurement mode. If set to None, will default to the current mode.
input_range

Gets/sets the device input range for the device range for the currently set multimeter mode.

Example usages:

>>> dmm.input_range = dmm.InputRange.automatic
>>> dmm.input_range = 1 * pq.millivolt

Units: As appropriate for the current mode setting. Quantity, or InputRange
mode

Gets/sets the current measurement mode for the multimeter.

Example usage:

>>> dmm.mode = dmm.Mode.voltage_dc

Type: Mode
relative

Gets/sets the status of relative measuring mode for the multimeter. This is an abstract method.

Type: bool
resolution

Gets/sets the measurement resolution for the multimeter. When specified as a float it is assumed that the user is providing an appropriate value.

Example usage:

>>> dmm.resolution = 3e-06
>>> dmm.resolution = dmm.Resolution.maximum

sample_count

Gets/sets the number of readings (samples) that the multimeter will take per trigger event.

The time between each measurement is defined with the sample_timer property.

Note that if the trigger_count propery has been changed, the number of readings taken total will be a multiplication of sample count and trigger count (see property SCPIMulimeter.trigger_count).

If specified as a SampleCount value, the following options apply:

1. “minimum”: 1 sample per trigger
2. “maximum”: Maximum value as per instrument manual
3. “default”: Instrument default as per instrument manual

Note that when using triggered measurements, it is recommended that you disable autorange by either explicitly disabling it or specifying your desired range.

Type: int or SampleCount
sample_source

Gets/sets the multimeter sample source. This determines whether the trigger delay or the sample timer is used to dtermine sample timing when the sample count is greater than 1.

In both cases, the first sample is taken one trigger delay time period after the trigger event. After that, it depends on which mode is used.

sample_timer

Gets/sets the sample interval when the sample counter is greater than one and when the sample source is set to timer (see SCPIMultimeter.sample_source).

This command does not effect the delay between the trigger occuring and the start of the first sample. This trigger delay is set with the trigger_delay property.

Units: As specified, or assumed to be of units seconds otherwise. Quantity
trigger_count

Gets/sets the number of triggers that the multimeter will accept before returning to an “idle” trigger state.

Note that if the sample_count propery has been changed, the number of readings taken total will be a multiplication of sample count and trigger count (see property SCPIMulimeter.sample_count).

If specified as a TriggerCount value, the following options apply:

1. “minimum”: 1 trigger
2. “maximum”: Maximum value as per instrument manual
3. “default”: Instrument default as per instrument manual
4. “infinity”: Continuous. Typically when the buffer is filled in this
case, the older data points are overwritten.

Note that when using triggered measurements, it is recommended that you disable autorange by either explicitly disabling it or specifying your desired range.

Type: int or TriggerCount
trigger_delay

Gets/sets the time delay which the multimeter will use following receiving a trigger event before starting the measurement.

Units: As specified, or assumed to be of units seconds otherwise. Quantity
trigger_mode

Gets/sets the SCPI Multimeter trigger mode.

Example usage:

>>> dmm.trigger_mode = dmm.TriggerMode.external


## SCPIFunctionGenerator - Generic multimeter using SCPI commands¶

class instruments.generic_scpi.SCPIFunctionGenerator(filelike)[source]

This class is used for communicating with generic SCPI-compliant function generators.

Example usage:

>>> import instruments as ik
>>> import quantities as pq
>>> inst = ik.generic_scpi.SCPIFunctionGenerator.open_tcpip("192.168.1.1")
>>> inst.frequency = 1 * pq.kHz

frequency

Gets/sets the output frequency.

Units: As specified, or assumed to be $$\text{Hz}$$ otherwise. float or Quantity
function

Gets/sets the output function of the function generator

Type: SCPIFunctionGenerator.Function
offset

Gets/sets the offset voltage of the function generator.

Set value should be within correct bounds of instrument.

Units: As specified (if a Quantity) or assumed to be of units volts. Quantity with units volts.
phase

Gets/sets the output phase of the function generator. This is an abstract property.

Type: Quantity