VirtualDMM#

class VirtualDMM( stimulus: dict[MeasurementFunction, float] | None = None, )[source]#

Bases: DMMDriverBase

DMM simulated in-process: no transport, server, or hardware.

Each function reads its stimulus value plus noise (0.5%, the SCPI simulator’s level). Range, NPLC, digits, and aperture settings are accepted and have no effect on readings, so any InstroDMM call works. To exercise the VISA transport as well, use SimulatedDMM with the bundled SCPI simulator.

Create a virtual DMM.

Parameters:

stimulus (dict[MeasurementFunction, float] | None)

The value each function measures before noise, in volts, amperes, or ohms. Functions left out keep their defaults (1.25 V DC, 0.5 V AC, 0.1 A DC, 0.05 A AC, 1000 ohms).

Example:

from instro.dmm import InstroDMM, MeasurementFunction
from instro.dmm.drivers import VirtualDMM

dmm = InstroDMM(name="dmm", driver=VirtualDMM({MeasurementFunction.DC_VOLTAGE: 3.3}))
with dmm:
    print(dmm.read_dc_voltage().latest)  # about 3.3

Methods

`close`	Nothing to disconnect.
`measure_ac_current`	Trigger an AC-current measurement and return the value (amperes RMS, vendor-dependent).
`measure_ac_voltage`	Trigger an AC-voltage measurement and return the value (volts RMS, vendor-dependent).
`measure_dc_current`	Trigger a DC-current measurement and return the value (amperes).
`measure_dc_voltage`	Trigger a DC-voltage measurement and return the value (volts).
`measure_four_wire_resistance`	Trigger a 4-wire-resistance measurement and return the value (ohms).
`measure_resistance`	Trigger a 2-wire-resistance measurement and return the value (ohms).
`open`	Nothing to connect to.
`set_ac_current_nplc`	Accepted; no effect on readings.
`set_ac_current_range`	Accepted; no effect on readings.
`set_ac_voltage_nplc`	Accepted; no effect on readings.
`set_ac_voltage_range`	Accepted; no effect on readings.
`set_aperture_seconds`	Accepted; no effect on readings.
`set_dc_current_nplc`	Accepted; no effect on readings.
`set_dc_current_range`	Accepted; no effect on readings.
`set_dc_voltage_nplc`	Accepted; no effect on readings.
`set_dc_voltage_range`	Accepted; no effect on readings.
`set_digits`	Accepted; no effect on readings.
`set_four_wire_resistance_nplc`	Accepted; no effect on readings.
`set_four_wire_resistance_range`	Accepted; no effect on readings.
`set_measurement_function`	Accept any function; `InstroDMM` calls the matching `measure_*` method to read it.
`set_two_wire_resistance_nplc`	Accepted; no effect on readings.
`set_two_wire_resistance_range`	Accepted; no effect on readings.

open() → None[source]#: Nothing to connect to.

close() → None[source]#: Nothing to disconnect.

set_measurement_function( function: MeasurementFunction, ) → None[source]#: Accept any function; InstroDMM calls the matching measure_* method to read it.

set_digits(n: int) → None[source]#: Accepted; no effect on readings.

set_aperture_seconds(seconds: float) → None[source]#: Accepted; no effect on readings.

set_dc_voltage_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_ac_voltage_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_dc_current_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_ac_current_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_two_wire_resistance_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_four_wire_resistance_range(value: float | None) → None[source]#: Accepted; no effect on readings.

set_dc_voltage_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

set_ac_voltage_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

set_dc_current_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

set_ac_current_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

set_two_wire_resistance_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

set_four_wire_resistance_nplc(nplc: float) → None[source]#: Accepted; no effect on readings.

measure_dc_voltage() → float[source]#: Trigger a DC-voltage measurement and return the value (volts).

measure_ac_voltage() → float[source]#: Trigger an AC-voltage measurement and return the value (volts RMS, vendor-dependent).

measure_dc_current() → float[source]#: Trigger a DC-current measurement and return the value (amperes).

measure_ac_current() → float[source]#: Trigger an AC-current measurement and return the value (amperes RMS, vendor-dependent).

measure_resistance() → float[source]#: Trigger a 2-wire-resistance measurement and return the value (ohms).

measure_four_wire_resistance() → float[source]#

Trigger a 4-wire-resistance measurement and return the value (ohms).

Default raises NotImplementedError; override on drivers whose instrument has dedicated sense leads (e.g. Agilent 34401A).