Been having a few issues with gradually loosing position on my DMM servo/drive on my 4th axis. Its being controlled analog with encoder feedback to kanalog. Everything works great with spindle off, did a bunch of testing/tunning and everything was spot on. But after running a few parts I noticed things are drifting off a little with spindle on.
Im using really nice double shielded encoder cable with shield connected to servo drive ground. And its only a short run of about 3ft. Kind of surprising this is causing problems as im using the same cable in much longer runs on my other 3 encoders (not DMM drives) and its working perfectly. I see another thread with similar problems on a DMM drive a month ago. I wonder if the encoder output from the DMM drives is causing problems?
Any suggestions on what else to try? Should I try connecting the shield to Kanalog ground instead of servo drive ground or is this a bad idea? Also the 220v single phase supply for this servo drive was taken from 2 of the 3 terminals of the spindle VFD, could noise be comming from these power lines and messing up the drives encoder output signals? I could take power directly from transformer output but its more difficult and only a couple feet away anyway.