Need help with FFT for Vibration Analysis

[Xtasy]

Hello all,

I am acquiring data into LabVIEW from an accelerometer. The acceleration (in g's as determined within MAX) time domain graph works fine. However, I wish to do analysis using an FFT spectrum. All my attemps at wiring my time domain acceleration data into various FFT.vi's have resulted in blank graphs, including the sound and vibration module VI's. I am accquiring at 2000Hz. Obviously I am doing something wrong. Can anybody shed some light on how I can get a successful FFT working?

Kind Regards

Adam

[SunshineDesign]

You have not included anything for us to look at to see where your issue might lie. There is no VI or Data provided to help analyze the issue.

[preston_johnson]

do you get any error codes from the FFT VIs?  A common error is that the time waveform data going into the FFT is NOT continious, meaing each data point is separated in time by the same delta-t.

[Xtasy]

My apologies for not including any code in my post, but I presently don't have access to it until next week, so I will do my best to describe it since it is a simple goal I am trying to accomplish. I can produce a comparable program on my home computer if necessary.

My raw data is pulled into LabVIEW as a DBL in units of g's as configured in MAX. I then use the build waveform function to assign a dt (1 second) and t0. My time domain data plots without issue. If i attempt to pass this waveform to the baseband FFT VI in the sound and vibration module and have the data plotted to graph, there is no visible plot. I receive no errors. I have also tried similar functions in LabVIEW such as the FFT power spectrum and PSD VI to no avail. 

[preston_johnson]

I attached an example that works well for me - gens a signal, converts to waveform data type, does FFT