Export 1st; 2nd; 3rd; up to 11th harmonic from LabVIEW graph to excel

[fezeka724]

Hi,

How do I export from 1st, 2nd, 3rd, 4th, 5th, up to 11th harmonics without exporting the other harmonics in between?  

Thanks in advance.

[santo_13]

You do some filtering on the FFT data and write only those filtered data to the file.

[Bob_Schor]

You show a picture of a plot that has peaks.  It is not clear what the real "data" are -- it might be a plot of an FFT of some waveform, but we'd need to see the LabVIEW code (a file with the extension .vi showing LabVIEW code, editable and runnable, not pictures of Block Diagrams, please) to understand what you want to do.

You should also clarify what you mean by "Export ... graph to Excel".  Your plot appears to cover the frequency spectrum from the first to 11th harmonics, though plotting with linear axes makes it difficult to see things clearly.  Have you explored changing the X and/or the Y Axes to logarithmic?

Please attach your code.  Since you are a New Member, you are probably using LabVIEW 2023 Q1, which many "long-time LabVIEW users" (myself, included) have not installed.  Before attaching your code, "Save for Previous Version" and choose LabVIEW 2021 or LabVIEW 2019.

Bob Schor

[altenbach · Accepted solution]

If you know the base frequency (probably around 50Hz here), you know the exact location of all harmonics and it seem trivial to index them out and e.g. place them in a table with two columns (frequency & magnitude) that you can write to a tab delimited file that excel can read. You can even create a real excel file with slightly more effort.

Once you attach your VI containing some typical data, we can show you how. It gets a bit more tricky in the presence of spectral leakage and such.