Encoder parity bit errors

[dmbartender]

Hi guys. I've got a machine using B&R as a positioning control, with Bosch Rexroth motors. In our plant the machine worked quite well, but at the installation I keep getting encoder errors on a couple of axes as soon as I switch the servo control on. It says there's a parity bit error. Sometimes this goes away for a while, but it always comes back, and it's always on the same axes.

I checked the wiring and connection of the encoder, and it seems to be fine. The errors occur on the motors that have the longest cable lengths, so I assume that EMF has something to do with it.

Is there anything I can do to remedy this?

 

[TimWilborne]

Check your shielding

 

[dmbartender]

I additionally grounded the shielding at the drive side. I was thinking of doing it at the motor side too, but am not sure how to do that

 

[TimWilborne]

How about the grounding itself? Can you provide more details?

 

[dmbartender]

the cable has a shielding, which is folded backwards onto the cable, and this has a band of copper on it. This is affixed to the connector. I attached a ground wire to where the shielding abuts the connector.