Hello, I am trying to measure the time of a single pulse using ctr0 on a PXIe-6361. The input signal seen in attachment Capture7.jpg, is going to PFI 9, the gate of ctr0. The problem is that the counter see' s the rising edge and stops. The pulse width is not given as can be seen in the output (Capture8.jpg). I get the same results using Meas_Pulse_Width.vi example. Is something wrong with my PXIe-6361?

Oh I think I know what it is. Change the task to "Pulse Width" (measures a single pulse) insted of "Pulse" (measures the high and low time of a repeating pulse). Modify the DAQmx Read to use Ctr>>Single Sample>>DBL (instead of Pulse Time). Modify the digital filter property node to use the corresponding "Pulse Width" properties (the filter is still necessary): The Pulse task was not timing out initially since you were getting a repeating series of noise pulses (and thus it was measuring a very low duration). With the filter it was timing out since the noise is now eliminated and the single pulse will not complete the Pulse measurement (which requires a high and a low time): For the record, I agree it is confusing that there is both a "Pulse" measurement and a "Pulse Width" measurement and they do different things. Best Regards,

Counter/Timer

single pulse width measurement

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Sucess!

The "Digital Filter" and changing the task to "Pulse Width" has led to repeatable measurments on all of the counters and different PFI inputs.

I have attached some images of the final results.

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Message 11 of 12

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In case anyone else needs to know:

This pulse measurment is for determining the time between two optical gates, so that the velocity of the striker can be determined on a tensile Split Hopkinson Pressure Bar.

The PXIe-6361 is being used for collecting the measurments of the optical gates and from the pressure transducer.

A PXI-5105 is being used to gather data from the strain gauges.