Questions about waveform integration

[EdmondDantes]

Good morning gents, I am new to Labview and I would ask you something about integrated waveforms.

I have a waveform signal and I have tried to integrate it in different ways (see pictures attached).

The results plotted on the graphs seems fine and right (I think integrated waveform 1 is the correct one), but I cannot understand well why in the other graphs the time scale on the x axis varies and why also the amplitude on the y axis is different in the integrated waveform 3.

I think that the problem regards the dt of the signal. 

I want also ask which are the differences between the integral blocks I used. 

Finally I would like to ask some suggestions on how to correct the visible "offset error" on the integrated signals and how to implement this offset error correction. 

[altenbach]

We cannot run or debug images. (Especially if there are express VIs, a lot is hidden from view).

Please attach your VI instead. Make sure it contains some typical default data for the signal array. Thanks.

(SIDE NOTE: to get an element of an array, "index array" is the right tool. Doing an "array to cluster ...unbundle" dance is not the right way...)

[EdmondDantes]

Thank you for your suggestion.

Here I attach my VI, it is basic and simple.

I cannot attach the data  I work with because the .pnrf is not accepted as a format I can send here.

But the signal that comes out from from the read data channel is an array of waveforms and every signal contains a current waveform and a voltage waveform.

[RavensFan]

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@EdmondDantes wrote:

I cannot attach the data  I work with because the .pnrf is not accepted as a format I can send here.

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But .zip files are an accepted format!  So just zip up your file and attach it.

[EdmondDantes]

ZIP FILE: I cannot attach the data I work with,but I attach a test .pnrf file with two sinusoidal signals.

You can import on labview via hbmpnrf plug in.

[crossrulz]

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@EdmondDantes wrote:

The results plotted on the graphs seems fine and right (I think integrated waveform 1 is the correct one), but I cannot understand well why in the other graphs the time scale on the x axis varies and why also the amplitude on the y axis is different in the integrated waveform 3. 

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The time scale issue to due to the fact that your last 2 graphs have nothing to give them a time reference.  Use Build Waveform to just change the Y portion of your waveform to use the new integration array.

The amplitude of the third waveform is different because you did not supply a dt.  Integration involves a multiplication of dt.

Here is a much cleaned up version of your code that should fix what you are having issues with.

[altenbach]

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@EdmondDantes wrote:

I cannot attach the data  I work with because the .pnrf is not accepted as a format I can send here.

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No need to attach the data. Simply run the VI until it displays typical data. Now right-click the terminal of the "Original waveform" graph, followed by "create constant". Now delete the upstream code, the constant has a copy of the data. Save the VI under a new name (it will be a little larger on disk) and attach it here. (Please also give it a reasonable and unique name to prevent confusion. My downloads folder already has several "Try.vi", so the browser will rename yours to e.g. Try(3).vi when I try to download, potentially making me to open the wrong code by accident. A better filename might be WaveformIntegrationTest.vi, for example)