Power Spectrum Viewing of MyRIO Accelerometer

[junlabView]

Hi,

I have been trying to display analog inputs from myRIO in-built accelerometer in the frequency domain using the Spectral Measurements vi. However, no matter how many sources and example programs I look at, I do not see the same issue shown below, whereby the data point remains at 0 frequency for the whole duration of the run-time. The magnitude (y-axis) changes. I honestly have no idea where this has gone wrong, except that the input 1D array into the Spectral Measurement seems to be an updated one element instead of an array of elements. 

Please if anyone could provide any guidance or an example set-up where this could be fixed, it would be much appreciated. Thanks. 

[dkfire]

How should it calculate the frequency of a one sample data? 

You need more points to be able to calculate FFT of any signal.