Cause : Feedback device comms failure comes when the Encoder 4 trip indicates that the encoder communications has timed out or the communications position message transfer time is too long. 

This trip can also be caused due to wire break in the communication channel between the drive and the encoder. The feedback device which has caused the trip can be identified by the sub-trip number. Sub-trip & Reason given below:

1 - Drive position feedback interface 1.
2 - Drive position feedback interface 2.

• Ensure the encoder power supply setting (Pr 03.036) is correct.
• Complete encoder auto-configuration (Pr 03.041).
• Check the encoder wiring.
• Replace the feedback device.