adxl 345 fft frequency

[lsh1103]

Hello Guys
I have one question...
I am doing fft analysis of the received signal using the adxl345 accelerometer and labview, but the maximum frequency is strange.
I know that the maximum frequency is half the sampling rate, but the sampling rate listed in the adxl345 catalog is up to 3200hz.
So, shouldn't it be displayed up to 1600hz when fft is performed?
However, when measuring at a sampling rate of 3200hz, the maximum frequency is only about 25hz.
And if you lower the sampling rate and measure, the maximum frequency goes up...
If you look at the time graph, you can clearly see that the sampling rate has changed.

 

This is the program I wrote. 
Is there something wrong with the program?

Uh... the frame rate might look weird, but it's just for changing the maximum frequency number displayed on the graph...

[l.hovs]

Hello lsh1103, 

There are many problems, that can cause this issue, for instance you have a lot of Coercion Dots, because of that you might resave a wrong data, also, I suggest connecting arrays with simple wires, besides local variables (in this case I think it isn't causing problem, but local variables use a lot of memory which you don't need in). 

I don't have any accelerometer in my side to check, so try to correct that and use some FFT examples given from NI to be surer, that you are resaving correct data. 

Regards)

[sasa_one]

sorry i can't help you, but i want to ask about these value 0,28125 and 5,1875. what do these values mean? Thanks 

[altenbach]

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@sasa_one wrote:

sorry i can't help you, but i want to ask about these value 0,28125 and 5,1875. what do these values mean? 

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Calibration offsets?