text: <s>[INST] PF525 auto tune failure Summary: Fail to auto tune Powerflex 525Twice in the last year I have been unable to auto tune a power flex 525 in fvc mode. Encoder is A quad B differential 12vdc. Motors have been SEW and Nord inverter duty . Encoder coupled to back of motor. Oscilloscope shows good amplitude, 90 degree phase shift, and minimal ringing. Changed A and A not signals to eliminate quad check error. Even went as far as swapping A and B channels. Auto tune feature always runs motor to 44.999 hz. and will never finish. When aborting auto tune, you get the abort error. Clear it and try to run. Error codes F13 ground fault or F7 motor overload occurs. Removed motor leads from drive, metered motor with no shorts or breakdowns. Using ACVF Lapp shielded cable for motor. Shield connected at both ends. Lowered F1 kp to F3 kp from 100% to 20%. No change in outcome. Tried static tune and motor runs at high speed. After aborting static tune, and place motor in run mode, motor accelerates to extremely high speed ( much higher than 60hz). Motor nameplate data matches P31 through P37. Replaced encoder card and also replaced drive. Eventually updated the drive firmware from 4.001 to 5.001. No change in results. I have never had this problem on any other power flex drives. Spent many days trying to resolve this issue and have given up. Any thoughts would be appreciated. [/INST] I've had similar issues with the 525. Im guessing that the motor will run fine in SVC mode, but as soon as you put it in FVC it either faults or fails to control speed. For FVC with an encoder to work correctly a successful rotate tune must be completed. Make sure your feedback type is set to Quad Check. Also, the forward direction of the motor must match the forward direction of the encoder. Double check the directions are the same and switch A and A- if they don't match. \\n </s>