Why do I get constant frequency?

[ashnu]

Hello !

I have connected a rotating blade rpm measuring device's digital input to the PXI-6251. I have kept the sample rate as 10kHz and number of samples to 1000. I ran the blades manually and got 500 rpm in the device and 677rpm in the labview. But after this when I don't run the turbine and just run the program, I am still getting 677 rpm or 11 Hz constant, whereas I should get 0 Hz right? Why is this happening?

[crossrulz]

Quit making new threads for the same problem.  Keep the discussion in your original thread.

Digital input to rpm

[meBaga]

How many pulse you will get at a full 360 Deg rotation? or what is the logic for the measuring device you are using?

Also when you need continuous data acquisition, try to avoid express VI, and make the code with daqmx low level VI.