Source Measure Unit¶

Auto-generated from driver source.

NI PXIe-4139¶

NI PXIe-4139 single-channel source measure unit (uses nidcpower).

NI_PXIe_4139 ¶

Driver for the NI PXIe-4139 SMU via nidcpower.

Exposes the same PSU-like interface that the REPL expects so it can be used interchangeably with SCPI-based power supplies.

Key nidcpower pattern: property changes (voltage_level, output_enabled) must be applied while the session is initiated (running). Set properties on-the-fly FIRST, then abort() to stop.

connect ¶

connect()

Open an nidcpower session and configure safe defaults.

The session is left in the Running state with output disabled. All subsequent property changes (voltage_level, output_enabled, etc.) are applied via commit() while running — NI-DCPower requires this. If the device is in OLP (Overload Protection), the session is opened with relaxed options to clear the latched state first.

disconnect ¶

disconnect()

Close the nidcpower session.

enable_output ¶

enable_output(enabled: bool = True)

Enable or disable the output. Session stays Running.

disable_all_channels ¶

disable_all_channels()

Set output to safe state: 0 V, low current limit, output off.

set_voltage ¶

set_voltage(voltage: float)

Set the DC voltage level.

set_current_limit ¶

set_current_limit(current: float)

Set the current limit (compliance magnitude, always positive).

set_output_channel ¶

set_output_channel(channel, voltage, current_limit=None)

Set voltage and current limit (channel arg ignored — single channel).

measure_vi ¶

measure_vi() -> dict

Atomic V+I+compliance measurement in a single session call.

Returns:

Type	Description
`dict`	dict with keys 'voltage' (float), 'current' (float),
`dict`	'in_compliance' (bool).

measure_voltage ¶

measure_voltage() -> float

Measure the output voltage.

measure_current ¶

measure_current() -> float

Measure the output current.

query_in_compliance ¶

query_in_compliance() -> bool

Return True if the output has hit the compliance limit.

set_source_delay ¶

set_source_delay(seconds: float) -> None

Set the source settle delay before measurement (0 to 167 seconds).

get_source_delay ¶

get_source_delay() -> float

Return the current source_delay in seconds.

set_voltage_mode ¶

set_voltage_mode(voltage: float, current_limit: float = None) -> None

Switch to DC_VOLTAGE mode and set the voltage level.

set_current_mode ¶

set_current_mode(current: float, voltage_limit: float = None) -> None

Switch to DC_CURRENT mode and set the current level.

get_output_mode ¶

get_output_mode() -> str

Return the active output mode: 'voltage' or 'current'.

set_samples_to_average ¶

set_samples_to_average(n: int) -> None

Set the averaging count for noise reduction (n >= 1).

get_samples_to_average ¶

get_samples_to_average() -> int

Return the current samples_to_average setting.

read_temperature ¶

read_temperature() -> float

Read the SMU instrument temperature in degrees Celsius.

get_voltage_setpoint ¶

get_voltage_setpoint() -> float

Return the configured voltage level.

get_current_limit ¶

get_current_limit() -> float

Return the configured current limit.

get_output_state ¶

get_output_state() -> bool

Return whether the output is enabled.

reset ¶

reset()

Reset the instrument — full session teardown and reconnect.

This recovers from hard errors like OLP (Overload Protection) where the session is unresponsive to normal commands.

query ¶

query(cmd, **kwargs)

Return an IDN-like string (SCPI compatibility stub).

send_command ¶

send_command(cmd)

No-op SCPI compatibility stub.

get_error ¶

get_error() -> str

SCPI compatibility stub — error queue not supported on NI_PXIe_4139.