Hardware-Requirements of Pulse Measurements

Updated Jun 6, 2018

Reported In

Hardware

  • cDAQ-9189
  • NI-9361
  • CompactRIO Controller

Software

  • LabVIEW

Issue Details

I would like to measure the frequency and the duty-cycle of a PWM-Signal (Pulse Width Modulated Signal) using a single physical channel and a single counter. Since they convey equivalent information, the high time and low time measurements of the signal with a single physical channel and a single counter would also be eligible.

I get the error message with the code -200431 in LabVIEW, if I try to use either of the CI-Pulse Freq, CI-Pulse Time or CI-Pulse Ticks variants of the DAQmx Create Virtual Channel.vi together with the physical channel of the NI 9361 Counter Digital Input module in a CompactDAQ chassis.
 

 

Solution

There are two possible solutions to the problem, both are requiring modification of hardware configuration:
  • Use the NI 9361 Counter Digital Input module together with a CompactRIO system. The NI 9361 supports pulse measurements only for CompactRIO systems.
  • Alternatively replace the NI 9361 Counter Digital Input module with a parallel digital I/O module in the CompactDAQ chassis. The NI 9344, NI 9401, NI 9402, NI 9411, NI 9421, NI 9422, NI 9423, NI 9435, NI 9436, NI 9437, NI 9472, NI 9474, NI 9475, NI 9481, NI 9482, and NI 9485 are parallel digital I/O modules.
With such hardware configuration both parameters will be possible to measure with a single counter using a single physical and virtual channel.

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