NI PXIe-4139 Setup

The NI PXIe-4139 is a ±60 V / 1 A four-quadrant Source Measure Unit (SMU). It uses the NI-DCPower driver — not VISA/SCPI — so it requires its own driver stack.

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Prerequisites

1 — NI-DAQmx runtime

Download and install from: NI-DAQmx Downloads

This installs the NI instrument driver runtime that the nidcpower Python package calls into.

Windows only

The nidcpower package and NI-DAQmx runtime are only supported on Windows at this time. The REPL loads the NI PXIe-4139 driver conditionally — on Linux/macOS the instrument is silently skipped.

2 — nidcpower Python package

pip install nidcpower

3 — Verify the DLL is found

After installing NI-DAQmx, the required DLL (nidcpower_64.dll or nidcpower.dll) should be in one of:

• C:\Program Files\IVI Foundation\IVI\Bin\
• C:\Program Files (x86)\IVI Foundation\IVI\Bin\

If Python can't find the DLL, add the IVI Bin directory to your system PATH.

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Hardware setup

1. Seat the PXIe-4139 card in the PXIe chassis.
2. Connect the chassis to the host PC via MXI-Express or Thunderbolt.
3. Open NI MAX (Measurement & Automation Explorer) and verify the card appears under My System > Devices and Interfaces.
4. Note the resource name shown in NI MAX (e.g., PXI1Slot2). This name is needed for manual Python scripts (see the example below). The REPL typically auto-discovers the card without requiring manual resource specification; the resource name is only needed as a fallback if auto-detection fails or you need to force a specific device.

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REPL auto-detection

When nidcpower is installed and the card is present, the REPL assigns the SMU as smu1 automatically on startup (or on scan).

eset> scan
[scpi] Found: smu1  (NI PXIe-4139)

If the card is not found, run scan after the chassis is powered and the MXI link is established.

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Minimal working example

# Verify nidcpower works outside the REPL
import nidcpower

with nidcpower.Session("PXI1Slot2") as session:
    session.output_function = nidcpower.OutputFunction.DC_VOLTAGE
    session.voltage_level = 5.0
    session.current_limit = 0.01
    session.output_enabled = True
    session.initiate()
    v = session.measure(nidcpower.MeasurementTypes.VOLTAGE)
    i = session.measure(nidcpower.MeasurementTypes.CURRENT)
    print(f"V = {v:.6f} V   I = {i:.6f} A")
    session.output_enabled = False

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REPL usage

Once detected as smu1, use the standard SMU commands:

upper_limit smu voltage 6.0
upper_limit smu current 0.05

smu set 5.0 0.02
smu on
sleep 0.5
smu meas v
smu meas i
smu off

See Source Measure Unit (SMU) for the full command reference.

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Troubleshooting

Symptom	Likely cause	Fix
ImportError: No module named 'nidcpower'	Package not installed	pip install nidcpower
nidcpower imports but smu1 not found	Card not visible to driver	Check NI MAX; re-seat card; power-cycle chassis
DLL load failed	NI-DAQmx not installed or DLL not on PATH	Install NI-DAQmx runtime; add IVI Bin dir to PATH
Resource not found	Wrong resource name	Open NI MAX and confirm the resource name shown there