Voltage Measurements using a SMU

Updated Nov 24, 2017

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

Driver

  • NI-DCPower

Issue Details

How do I make a voltage measurement with a Source Measure Unit (SMU)?

Solution

Voltage measurements can be made with an SMU by setting the SMU to DC Current mode with the current level set to its minimum value. Configuring the SMU in this manner will allow the module to sense the voltage on its terminals while allowing minimal current to flow through the module. 

Follow these steps to use your SMU as a DMM to make voltage measurements:
  1. Go to Start » Programs » National Instruments » NI-DCPower » NI-DCPower Soft Front Panel.
  2. Set SMU Output Function to DC Current.
  3. Set SMU Range to smallest current range.
  4. Set Current Level to lowest possible value (refer to table 1).
  5. Click Output Enabled.

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.

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