BTW, who else out here is doing industrial controls (PLC
and the like).  Might be nice to have a list of those so we can compare
notes and problems away from the list.

I work for a comany that does industrial controls in the Boise, Idaho area.

>From Peter Neubert's questions, I would estimate that he has about a year of serious study before he can piece together what he wants.  I would recommend that he look to a major PLC supplier for a solution.  (Please don't take this as an insult -- I'm working down that road myself.)

Incidentally, microChip is supposed to be coming out with a PIC with a CAN interface.

Also, while CAN is a good networking system, there are some environments where field busses are NOT a good idea.  I'm still not sure if I like the idea of a network controlling the brakes in a car.

I'm also leery of using PC's as a controller.  Think how often your PC crashes, then decide if your factory can deal with that kind of down time.  Alos, think about the safety implications.  If a desktop PC crashes, it might take out the data on a hard drive at worst.  If an industrial control has a problem, it can take off an arm or smash someone's head.  (This is also something to consider when brewing your own control.)