FFT for multiple channels

[MikeFJ]

Setting up the VI like that still only runs one waveform through the FFT at a time. I want to run all of them through the FFT and display all the outputs at the same time on the same plot. That method only displays one output at a time.

[Dennis_Knutson]

Putting your code inside a for loop that indexes the waveform array is a simple solution.

[MikeFJ]

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@Dennis Knutson wrote:

Putting your code inside a for loop that indexes the waveform array is a simple solution.

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I have tried that, but can not get it to work. Would it be possible  show me how you would format it?

[Dennis_Knutson]

Here's a mod of Lynn's program. Took 30 seconds to change.

I would recomend you take the free LabVIEW tutorials and pay special attention to how for loops work, especially the auto-indexing feature.

[MikeFJ]

I have tried that exact configuration and it did not work. Did the vi you posted work for you, cause it does not display the output correctly when I run it (which is the same thing that was happening to me earlier).

[Dennis_Knutson]

Well, I forgot to wire a false to the 'compute frequencies' input but it worked as well as with a single waveform - meaning I am running in simulation mode so I have no signal to input and have no way of judging what the fft for a single waveform is supposed to be.

[johnsold]

After you go through the tutorials as Dennis suggested, run this version to collect some typical data.  Then follow the instructions on the front panel to save the data and post the modified VI with data.

Lynn

[Dennis_Knutson]

And here's a version that uses the  polymorphic FFT Spectrum function set for N Channels. No for loop and it works directly with waveforms.

[MikeFJ]

I should be all set, thanks for the help.