I'm not sure, but the modifications needed to convert a regular step/dir (velocity stepgen with PID) over to use encoder feed back is pretty minimal. Just connecting the encoder feed back to the PID loop instead of the step-gen's feed back.
I've been running a machine with this type of set up for a few years now, but I don't remember exactly how I built the config files, (I may have used Pncconfig for part of it or built off of others example files or a combination of both.)
