Slow FPGA Loop Rate when Taking Temperature Measurements on CompactRIO

Updated Mar 27, 2023

Reported In

Hardware

  • NI-9212
  • CompactRIO Controller

Software

  • LabVIEW
  • LabVIEW FPGA Module
  • LabVIEW Real-Time Module

Issue Details

I am acquiring temperature with the NI-9212 on my CompactRIO-9063's FPGA. I place an I/O Node inside a While Loop and my loop rate seems very slow, even though I set the FPGA to its 40 MHz clock. Why is this happening?

Solution

The FPGA loop speed is dictated by how fast the sampling rate of your module is. Temperature modules in general have very slow sampling rates, so it is slowing down your loop. Consider taking temperature measurements on the Real-Time Operating System of your CompactRIO.