text: <s>[INST] Ultra3000 E20 fault I have three machines with an Ultra3000 drive using sercos interface. All three machines have very similar design and are less than 2 years old. Two of the three machines have E20 faults intermittently. The newest machine is the one that doesnt fault on E20. I have talked to AB and tried all the likely solutions (changed motor, cables, routing, grounding techniques) but nothing seems to help. We may get rid of it for a while, then it appears out of nowhere again. The two machines that are faulting out are fed from the same 575 V sub, but we do have isolation transformers. The machine that isn't faulting is fed from a different 480 V sub. Just wondering if it is a power/harmonics issue? Has anyone had this issue? [/INST] Just out of curiosity, have you matched the firmware of the newer Ultra 3000 to the older ones? \\n </s>