ok, so I'll partially answer my own question. I found the spec sheet here:
http://www.usdigital.com/products/en...rotary/kit/e4p
this is all based on the AEDR, spec sheet here:
http://www.usdigital.com/products/aedr/
So, I get "what" it is, so how do I use it? It's got two channels of output which allow you to tell if you are going clockwise or counterclockwise by comparing the outputs. Can you do this on the cRIO or do you need something else to do the processing? Do you have to make your own splitter cable for this?
Thanks in advance.
Alan