PCIe 6321 Analog Input Reading Voltage When Not Connected to Sensor

Updated Apr 17, 2018

Reported In


  • PCIe-6321


  • Measurement & Automation Explorer (MAX)

Issue Details

The AI line on my card is oscillating between 10V and -10V when I read it and it is not connected to anything. 


We do not spec our hardware when not connected to a sensor, and it may show unexpected readings when not connected to any input. Please test the card when your sensor or other input is connected by using the NI-MAX test panels.

If you still see the oscillating voltage when a sensor is connected, it's important to check that everything is grounded correctly. This behavior most likely occurs due to a floating ground.

To test that your card is functioning correctly, please connect your Analog Input (AI) directly to the Ground. It should not show any oscillating behavior when connected to ground, though it may show noise near 0V. If it is still showing oscillating behavior above 1V even when directly connected to ground, please contact National Instruments support at ni.com/support 


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