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On-Demand Acquisition time-stamp issues

Hi all,

 

In reference to a problem I had earlier regarding Labview (http://forums.ni.com/t5/LabVIEW/incorrect-time-data-after-reading-measurement-file/m-p/2341184#M7324... I soon realized that it was a data acquisition issue rather than a Labview issue hence my post on this board.

 

To elaborate, I have a M-series PXI-6221 DAQ that I used to collect data with on-demand timing. This results in multiple data points being seemingly written to the same time-stamp. I attribute this to the DAQ reading as fast as it can, and subsequently generating these timing glitches. Normally, this wouldn't be a problem in a graphing program set to scatter mode, but it does pose significant challenges when I try to process this data in Labview since the timing is completely changed.

 

Is there a way to stop the DAQ obtaining data points in such a fashion? I was thinking of placing a time delay of 1 ms or so, but that seems like a very crude method of solving this problem.

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Hello mlau,

 

You could use continuous sampling instead of on demand. Use a sampling rate of 1000Hz for data points every 1ms. (Frequencty = 1/Period)

 

Thank you,

 

Joel Carroll

Applications Engineer

National Instruments

 

 

 

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