How to stop the counter after getting maximum amplitude from a waveform graph?

[Mal1279]

I am using accelerometer, optical encoder and daq card (PCI MIO 16XE10) for my tyre balancing project. Basically i am trying to stop my edges count from the optical encoder to get the position for putting the mass for correcting the balancing. Could anyone please help me by telling me how i can achieve it or is there any other ways to get the position using the daq card? One more thing, could anyone tell me how to change the waveform graph to frequency domain instead of time domain?

[gbush]

Time to Freq is easy. 1/time = freq. example. 1 msec period = 1000 hertz (1kHz).
I guessing you are attempting to design a new spin balancer for tires. I would record the entire "spin cycle with index count" then search the resulting waveform for the max amplitutes. Correlate the indexes and that should give you the high point and location. You might want to count the number of revolutions, then grab that 60% of that number of peaks.