Locking indexer issues

Are there any known issues with the "locking indexer" function? While rotary is locked with air brake, and servo is on hold (no command input to servo), encoder walks out of position until estop is caused by following errors. The servo shaft is not turning and rotary is not moving so this is a tough one to solve.

So you are saying that even though everything is mechanically locked your encoder is counting up or down?

If that is the case you need to check for an electrical problem in your encoder system. Either it is picking up electrical interference causing false counts, or there is a short or bad connection somewhere causing false counts.

Check your grounds, are you using shielded cables, are the shields properly grounded (at only one end).

Yes, mechanically locked and encoder freaks out as soon as a milling load is applied to part. When tool contacts part, it initially might fluctuate 1 or 2 encoder counts, then over a few seconds, with no mechanical movement. Encoder counts freak out and following errors trip estop.

Yes, shielded CAT6 cable with proper shielding on one end. I'm suspecting a faulty drive if there's no known bugs with locking indexer function.

Is there a way to ignore position of A axis while brake is locked? It would at least help me with diagnosing.

Have you tried plotting the encoder A and B signals with Halscope when the problem is occurring and when it isn't for comparison. Also, looking at those signals with a real scope might be enlightening.

It's showing over and under shoot but nothing is mechanically moving. This is a DMM DYN4 which simulates encoder counts to feed 7i77. It does not actually directly pass through raw encoder signals.

All bets might be off then. Is the drive being disabled when in "locked" mode?

You might need to contact DMM and ask their opinion what might be going on with their goofy encoder.

Yes, drive is "disabled". DMM has a "SHOLD" input that is verified functioning. They call it a servo hold which is goofy. Faulty encoder or drive most likely.

You sometimes can improve the shilding against high frequencies when you connect the free shield end via a low inductive capacitor. Fx. a ceramic one.
Mike