Current and Voltage Measurements Using NI PXI(e) SMUs in InstrumentStudio

Updated Nov 17, 2022

Reported In

Hardware

  • PXI-4130
  • PXI-4132
  • PXIe-4136
  • PXIe-4137
  • PXIe-4138
  • PXIe-4139
  • PXIe-4144
  • PXIe-4141
  • PXIe-4145
  • PXIe-4143
  • PXIe-4140
  • PXIe-4154

Software

  • InstrumentStudio

Driver

  • NI-DCPower

Issue Details

How do I make a current or voltage measurement using an NI PXI(e) Source Measure Unit (SMU) using InstrumentStudio?

Solution

Follow the respective steps below in InstrumentStudio to take voltage or current measurements with your NI SMU:

Current Measurements
  1. Set the SMU Channel <Channel Number> Output Function to Voltage.
  2. Set the voltage Level to 0V.
  3. Set the current Limit to a value appropriate to your region of interest. Note: This value must be higher than the expected current reading or else the SMU will limit the current.
  4. Set Output to ON.
Voltage Measurements
  1. Set the SMU Channel <Channel Number> Output Function to Current.
  2. Set the current Level to the lowest possible value (refer to the table below).
  3. Set the voltage Limit to a value appropriate to your region of interest. Note: This value must be higher than the expected voltage reading or else the SMU will limit the voltage.
  4. Set Output to ON.
Note: The PXIe-414x and the PXIe-4136/4137/4138/4139 have the added advantage of a 0A current level allowing it to sink 0 current; this is crucial when measuring high impedance voltage sources. All other SMUs will have a non-zero current which will be sinked in the SMU. The following table lists the minimum current levels of SMU devices. 
ModelChannelCurrent RangeMinimum Current Level
PXI-4130*1200 uA4 uA
PXI-4132010 uA0.2 uA
PXIe-4136 / PXIe-41370Any0 mA
PXIe-4138 / PXIe-41390Any0 mA
PXIe-414xAnyAny0 mA
PXIe-4154*030 mA0.1 mA
*Channel 0 and 1 may be used on the PXI-4130 and PXI-4154 respectively, but will have higher minimum current values than listed in the above table.

Additional Information

An SMU during operation will always be both sourcing and measuring while regulating either voltage or current. By configuring the SMU to output at 0 volts or amps, you are forcing to it behave like a ammeter or voltemeter, respectively. 

If when trying to read voltage input using PXI(e) SMU Card, an Overload Protection (OLP) warning is given, try the following steps:
  1. Connect the SMU card to an open-circuit and take the first few readings from it.
  2. Pause the data acquisition and connect the required device under test (DUT).
  3. Begin the voltage acquisition from the required DUT.

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