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PXI 4071 current measurement slows down after 500 seconds.

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I am measuring the current draw of a square wave through a material. The system starts out taking about 40 S/s as shown here,

 

start.png

 

However, after 500 seconds the current measurements slow down to about 20 S/s as can be seen here. end.pngIs this a hardware related issue (e.g. I don't have enough RAM, 2 Gb, on my PXIe-8820)?  In the code, I am waiting until the end to save the data, a 3.5 Mb file but this file size has not been an issue with other I/O setups.  

 

Thanks in advance,

Austin.  

 

 

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Accepted by Austin-Downey

Hey Austin, 

 

A LabVIEW memory consideration could very well be the issue here. If you were, for example, controlling the sample rate with a while loop in LabVIEW and storing data points in shift registers, we would expect to see this type of behavior over time. Would you be able to post code (or a screenshot) so that we could gain a little more insight into what's going on here?

 

Best,

Sam R.
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Its been a year, but I should reply for the sake of others. 

 

It was a memory problem. The embedded system we were using only had 1 Gb of ram. This was solved by slowing down the acquisition speed and taking the time stamp of every sample for post-processing.  

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