FFT of 20 waveforms

Hi,
I used the following VI (attached to the mail) in the past that acquires data from the specified channel, scales the data to engineering units, windows the signal, and performs the requested averaged frequency measurement. Power Spectrum, Power Spectral Density, and FFT are available frequency measurements. The resulting spectrum is displayed on a waveform graph.
You can find the VI on this link :
http://www.ni.com/example/30505/en/
However, I have now 20 waveforms graphs of 'voltages v/s time' that are the results of a FOR loop (see attachment: Capture.PNG).
I wish to perform the FFT of these waveform graphs together using the same VI.
However, I don't really know what to remove from this existing VI and where I need to connect the output of my waveform graphs to perform the FFT.
Thank you for your help.
Regards,
Attachments:
zoom_fft_daqmx_simulated.vi ‏94 KB
Capture.PNG ‏5 KB

I gave a try, but still some errors.
(see attachment)
Attachments:
Capture1.PNG ‏39 KB

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OK, that's a really good point, i am agree with it.
do you have made a study of the relationship between the sampling frequency and the maximum frequency of the signal?.
i am going to make it anyway, but to compare...
another point related to the waveform integration:
i rote in an application note that it is recommended to use a FIR filter instead of an IIR because it has less phase distorition of the signal. however, if you ask for the filter information and plot the "phase H(w)", you will se a big distortion in phase introduced by the filter.
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