PXIe-6614 Calibration Procedure in LabVIEW

Updated Jun 15, 2018

Reported In

Hardware

  • PXIe-6614

Software

  • LabVIEW

Driver

  • NI-DAQmx

Issue Details

I was looking at the PXIe-6614 Calibration Procedure, and I want to do the Verification section in a LabVIEW VI.
  • I followed the steps explicitly from the procedure, and got something similar to the diagram below.
  • VI doesn't run for 40 seconds. It runs "instantaneously," and I get much lower edge counts than I expected.
Is there anything I need to add to the procedure when programming in LabVIEW specifically?

Solution

The steps in the procedure are intentionally vague so that verification can be done in a variety of coding languages. Following the steps explicitly, the VI executes instantaneously because nothing is checking to see when the 40 second Counter Output task is done executing. The DAQmx Read is occurring right away, so it is only capturing the number of pulses since the Counter Output task starts (near instantaneous instead of 40 seconds).

You will need to add a loop that checks to see if the Counter Output task finished, then reads the Counter Input value. This also assumes that there is a valid synchronization time base going into the PFI line called out in the DAQmx Channel Property Node on the Counter Output task.



The attached VI is set by default to run with the PXIe-6614 in Slot 2 with the external timebase connected to PFI 39.

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