Somebody recently posted a similar thread in the programming forum, without too many takers:
http://www.chiefdelphi.com/forums/sh...=shaft+encoder
Maybe you'll have better luck here with the hardware guys. We've got lots of experience, and depending on your point of view it's good or bad. They work most of the time, but it's that small percentage of time they don't that we've gotten our butt kicked. Because of their location at the stiff wheel structure they're susceptible to high shock loads so we've had alot of failures (either electrical or alignment) at critical points in the match. I'll have to defer to my controls team to give you the specifics on which models we've tried and why - I'll make sure they see this thread.