You got a DRES on the processor board? That fault can occur for other reasons too. I.e. Power outage or drive turning off. UXOM maybe the uncontrolled movement code. if you have an Ovf20 drive, I would explore the fault log there for more info on the type of shutdown. The fault management on that processor subsystem can be spotty due the fact that it was used in multiple applications at that time.
