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Timing of Zoom FFT in Producer/Consumer Pattern with DAQ

Hello everyone, after reading endless hours of useful answers here, I can't find a solution for my problem and have to ask for your advice:

 

I'm building a vi to measure, evaluate, show and save vibration measurements. I use a Producer/Consumer pattern and I will get my data from an NI Acceleration Sensor. Therefore I currently use the DAQmx signal simulation.

In NIMAX I have a sample rate of 1000hz, continuous reading, buffer 20000 samples (-> attached vi)
The data runs into the ZoomFFT.vi of the Sound and Vibration Toolkit, cause I want to analyse a certain frequency area with a certain delta_f (0.25hz).
This works and atm I get every 4s a new FFT of the desired area.

 

My question now is how do I get a ZoomFFT of 5s of the acquired data. Or longer, 10s, 20s. How is the amount of data which flows into the ZoomFFT defined? At the moment, as far as I understand: 4s of the gathered data is analyzed.

 

Ive attached a simplified VI of my current VI. Further calculations with the FFT values are missing.


Attached VI: LV 2012

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Hello SepNI,

 

did you solve the issue in the meantime?

I would suggest that you increase your sample rate (if it's possible with the HW) to 4kHz and than use a standard FFT with delta_f(0.25hz).

 

Best Regards

 

 

 

 

 

 

Roman Rolnik
Application Engineer
NI Germany
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