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Configuring time stamps for writing waveform data to text file?

I prefer to avoid using Express VI's if I can help it. I discovered recently, through reading the forums, that the Write To Measurement File Express VI prevents the user from configuring the digits of precision in the output file, fixing them at 6. I have rewritten my VI, in an effort to use lower level file I/O to circumvent this issue. While I now see all the digits of precision my cDAQ modules can muster, I am unable to configure the time stamp such that t0 is set to 00:00:00. I want a single time column with the correct dt increment, starting at 00:00:00.000000. Is there a way to do this easily, within the existing structure of the my VI? Thank you all for your help!


I am using LabVIEW 2017 v17.0f2

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Message 1 of 4

Isn't what you are doing now working for you and showing you 6 decimal places for seconds?

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Message 2 of 4

Hi RavensFan, thanks for the response!

Yes, the code does give me the number of decimal places I want, but the time stamp does not start at 00:00:00. Instead t0 is the current local time, and the dt derived from the cDAQ module onboard clock is added to that iteratively. At least that's what I understand to be happening. What I'm really looking for is a high precision "elapsed time" stamp to go with the DAQ Y values, derived from the modules. Back when I was using the Express VI, this was all handled automatically - but I want to avoid Express VI's for any code I develop from now on 🙂

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Message 3 of 4

Yes.  t0 is the current PC time when the capture starts, and the intervals are dT and based on the DAQ board clock.


If you want your data to not be based on local time, but start at time=0, then just bundle a 0 into the t0 element of the waveform cluster.

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