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Recording time to File

Recording time to File

Hi,
The aim of my vi is to take the time between successive switches being broken/made. (characterised by an increase above a threshold volatge)
I am trying to use the get time/date to give me the time at which the events occur I can then manipulate this data in excel.
In this vi I am taking readings for whenever this characteristic is true to give me a set of data.
However it is unable to record propely, is there something very obvious that I am doing wrong?

Another issue I have which I am currently try to bypass by using excel, is that I only want to record the first time/date value. Is this possible?
This would eliminate the need for excel altogether. 

Is anybody able to help me?



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Message 1 of 8
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Re: Recording time to File

which time are you using?

unable to see your VI ( having 2009 )

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Message 2 of 8
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Re: Recording time to File

I have attached a screen shot of the vi.
I am using get time/date in seconds. However reading some of the posts on here I dont think this will be accurate enough as I am looking for microseconds timing.


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Message 3 of 8
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Re: Recording time to File

you cannot get microsecond timing on windows ( and your DAQ read function , conversion to DDT and write to spreadsheet file would not give you microsecc)

You can directly use get date time string but it will give you only sec

Message 4 of 8
(189 Views)

Re: Recording time to File

Would there be any way to do this.
I have put together the crudest of programs which uses DAQ assistants. Which simply gets data and records it.
If export data to excel then I can get the sort of accuracy I would like if I read off of the graph.

Have you got any pointers.
Thanks

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Message 5 of 8
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Re: Recording time to File

You lose the timing information when you convert to the dynamic datatype.

Each waveform acquisition returns a t0 value which you can use.

 

For the microsecond accuracy you are looking for, I would recommend doing a fixed rate acquisition instead of the point by point in a loop method.

 

Message 6 of 8
(175 Views)

Re: Recording time to File

I have attempted to use a known sample rate etc to get the data.
I have attached the vi in an earlier version of labview if this helps.
I have taken out the convert to dynamic data, but I am struggling to extract the data from the waveform data.

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Message 7 of 8
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Re: Recording time to File

I think you want Get Waveform Time Array.

It's on the Waveform palette.

Maybe in combination with a Get Waveform Component to grab the data.

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Message 8 of 8
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