Regarding Buffered period measurement.

[smenon]

Hi,
I am using a 6052E series DAQ card to read a square wave signal. I am trying to use the buffered period measurement sample vi to read the period of the wave. There are a couple of things i dont understand about this sample.
1. How do you specify the number of data acquisitions to make/ how many scans are stored into the buffer in one acquisition. Because i plan to average these measurements to get the average period measured and hence the average frequency.
2. What values are stored into the buffer? The period measurements from the wave or something else.
Right now i am unable to see what the data is because the buffer comes out empty. I am triggering the VI using the pulse from the scanclock pin which turns high every time a scan is made of the analog channels connected to my SCXI chassis.
Thanks in advance,
Shyam.

[AlanArmstead]

Hello,
I'd like to help you out. I've got a couple questions and some comments: Are you using LabVIEW, if so, which version? Are you using DAQmx VIs? Do you have a recent version of NI-DAQ (7.3.1 is the most recent). I've attached a LabVIEW example that uses DAQmx VIs to do buffered period measurements. I used it with my E Series Device. I connected the signal I wanted to measure to the source of Counter 0. Set "Samples Per Channel" to the number of period measurements you want it to take. The results will be in the "Data(sec)" array.

Just one other thing:
Is your overall goal to find out the exact sampling rate? You can query the driver to find out the exact sample rate that the DAQ device is using. Use a DAQmx Timing Property Node and select Sample Clock >> Rate.

-Alan A.