Cause : PU communication internal comes when internal communication error. The PU in your ABB ACS880 drive is a crucial component responsible for power management and control. For proper operation, the PU communicates internally between various sub-modules to exchange data and control signals.

The fault code 5E09 in your ABB ACS880 drive indicates a PU communication internal error. This signifies a problem with internal communication within the Power Unit (PU) of the drive.