Creating FFT from 1D-Array continously

[MaddoxX]

Hey Guys,

Im doing vibration measurements with a accelerometer on my mydaq. I allready get my timesignal readings correctly. Afterwards I save those readings in a 1 D array. Now I want to perform a FFT spectrum.
But the shown FFTs are useless es they are not displaying anything useful. I tried before to take an FFT va the express.vi and this worked perfectly. Got the spectra as excpected and worked fine. But as Im not allowed to use express.vi s in my project I can not use it.
So any help would be highly appreciated as Im getting nuts with it and Im trying since 3 days to get this run...

Thank you very much

LabView 2014

[Dennis_Knutson]

From the images you posted, the code is not very well written, in my opinion. The event structure is unnecessary. If you would acquire N samples, you wouldn't even need to build an array. You appear to be using software timing so the fft result would be suspect. The stacked sequence structure shouldn't be used at all.

[MaddoxX]

Thanks for the fast answer,

as I just started 2 weeks ago with labview i guess that i miss some knowledge for a nice written code. My try would be to have a continous recording and displaying as fft without express.vi.

Can you please be so kind and give me some input so that I can follow up on that?

Thx

[Dennis_Knutson · Accepted solution]

Configure the DAQmx Read for N samples. Set it to return a waveform data type. Wire it to your fft function.

[RavensFan]

Another tip is to use the Express VI, then right click on it and pick Open Front Panel.  Now you will have a regular subVI.  Open that up and drill down through it to see how it is programmed.  You'll learn from that and can try replicating the parts that do what you need to do.