Hello everyone, I´m sorry to create a new subject, i tried to find solution by myself everywhere, but with no success.
Iˇm trying to read a frequency with NI9401 and cRIO.
After i will set 800Hz on frequency generator (i did test it with oscilloscope, output is really 800) and i´ll connect it to 9401, I´m getting frequency which is jumping from +/- 793 to 823. (i connected CTR0 to pin 14 and ground to COM)
It does´t matter if i´ll set 50Hz, 500Hz or 5kHz, the "jumping" is still there. (Time on the loop is 200ms just to see the values, usually i leave it on 10but then, the values are jumping so fast it´s more like blurry number - illegibly).
Chassis is set on scan mode, i checked the electrical connection, cables etc, those things should be ok. I tried to put 9401 into DAQ and read freq. through NI max, and there, i´ll get 800Hz almost exactly. So i believe it is cRIO and labview programming problem.
My question is, why is it acting like this ? Is possible to get "straight" frequency from 9401.. ? If yes, what should i change?
//..my amateur opinion, I have the feeling I´m getting "bottom and peek values of amplitude" from the graph (pic below), which is not what i want 🙂 .. but maybe you guys know how to get accurate freq from this or what else i did wrong. I´ll be grateful for any advice. Thank you. 🙂
I used example from here.