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Making Transition from DaSyLab to Labview


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After using DaSyLab for 8 yrs. I am now trying to work with Labview 8.5 and the biggest hurdle I am trying to overcome is the different "terminology" of the two.

I have set up a basic NI-DAQ system (in this case using a PCI-6071E card). I set up the DAQ Assistant for "Continuous Samples" at 100 samples to read and at a rate of 300HZ. I am scanning 2 channels and coming out of the DAQ Assist through a Filter and from there to simple digital meters on the front panel. All this seems to work OK.

I am trying to record data from 2 channels in the "Write to Measurement File" as text and 1 file. Reading this data in Excel works well except in no time I have a large file...as would be expected.

In DaSyLab there is a module called a "Seperate" module. If the DAQ hardware is running at 300 Hz you can tell the module to take 1 sample at start.....skip 2999 samples and then take 1 sample....and do this continuously. This gives you a "sample record" rate of 1 sample every 10 seconds and comes out in a "very manageable" single ASCI file in Excel over a length of time. As I run testing on various equipment and components....1 test may go for days on many channels, so this sampling rate is a definite need.

I have hunted and searched for days now in Labview and on the internet and cannot find what I am looking for. Can someone steer me to the .VI or whatever it is that I need to accomplish the data reduction?? I can't believe this should be this complicated....but I think the terminology I am used to is not matching the terminology I need to know.

Any help is greatly appreciated and thanks in advance!!

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I don't have experience with the Write to Measurement File VI (most professional developers avoid using Express VIs for most things), but here's one simplistic option of how this can be done:

post-1431-1211220382.png?width=400

If this doesn't help you, you should upload the code you already have.

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QUOTE (Yen @ May 19 2008, 01:07 PM)

Thanks for the reply and suggestion.....but.....

Somehow I'm thinking if Labview is using the "dynamic data" VI's....there should be a quick way to reduce the amount of data being sent to the Write to Meas. file. Hopefully I can figure it out...

I'll upload the VI that I'm working with....and it is very basic and probably crude....to say the least....

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I have zero experience with the dynamic data type and the express VIs it uses, so I can't really help you, but the VIs in the Express>>Signal Manipulation palette should help you.

Specifically, you can use the conversion VIs on the bottom to convert to a 2D array and get the data you need out of that and then convert back, but the sample compression VI might also do what you want.

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