I have a MDC1460 configured in velocity control. The velocity control has behaved reliably up until now and seemed well tuned. I had a failure recently where the motor was commanded to move at 0rpm, but it was actually turning slowly. Logs indicate that the tick count from the encoder was changing between 3 sequential values during this time, but not going outside those values. It seems like it was an encoder failure that resulted in the PID loop losing its feedback signal. However, when I try and replicate this by introducing noise into one of the encoder wires, the drive shuts down in what I assume is a safety response. Our customer service people have already replaced the parts on the device in question, so I don't have the opportunity to inspect the encoder myself, and I am trying to reconstruct the failure from logs. I would appreciate any feedback from anyone who has seen a failure like this before.