measure phase difference between 2 signals

[rvn10]

I am very new to labview. i m trying to use labview to measure phase between 2 signals from encoder. I also want to measure the state of 2 quadrature square signals. anyone has any idea how to do it?

[Philip_Courtois]

Hi "rvn10",

Quadrature encoders do by nature have a phase difference of 90 degrees between channel A and B. This phase difference is required to know in which direction the shaft is rotating when a transition from one of the channels is received. Please see these two links for some useful information:

Encoders
Quadrature Encoder / Position Measurement

If your goal is to measure the angular position using the two quadrature square signals, then your task is quite simple if you use one of our Counter/Timer cards. Check for example the shipping example called "Measure Angular Position.vi".

If you want to read more about our most affordable Counter/Timer product, then check this link:

NI PCI-6601

Please let us know if you are using different hardware to acquire the signals.