Is External Power Supply Required To Measure 4-20mA Current on NI 9207?

Updated Nov 7, 2023

Reported In


  • NI-9207

Issue Details

I would like to measure 4-20 mA signal using the NI-9207. The external device is supplying the 4-20 mA current. For this card, do I have to connect the Vsupp input or is that optional for when I'm measuring an externally powered transducer? 


An external power supply for the NI 9207 is optional if your device has its own power supply to drive the current. 

You can connect one end of the device to the AI channel and another to the COM channel to make this kind of measurement.