Different Results When Measuring a Signal With External and NI Hardware

Updated Apr 21, 2022

Reported In

Hardware

  • CompactDAQ Chassis

Software

  • LabVIEW
  • LabVIEW Advanced Signal Processing Toolkit

Driver

  • NI-DAQmx

Issue Details

I can see some incorrect peaks of data when measuring from a volume flow sensor with DAQmx. Constant signal and volume flow are displayed on the control side of our system. A look with an oscilloscope also confirms that the sensor's outgoing signal is constant and matches the display in the frequency/analog converter.

Solution

Most possibly the DAQ cards have a higher sampling rate and are more sensitive thus resulting in the difference of measurement between NI hardware and external oscilloscopes, etc. In order to solve the issue, we would like to suggest using filters. You can use filters for your specific tasks from our Signal Processing-> Filters panel.