Quote Originally Posted by Ioannis View Post
If your ADC is the ADC inside the PIC then it is a possitive value.

If you use external ADC then I guess it can be negative also.

Ioannis
I am using the internal ADC on the PIC18F45K80 but the question I was having was determining if I was inside a window of +/- 40 counts. I was concerned that RefPosition - CurPosition could give me a negative result but I see how to handle it now. Thanks for all the help.