Cause : INU-LSU comm loss comes when DDCS (fiber optic) communication between converters (for example, the inverter unit and the supply unit) is lost.

The fault code 7580 in your ABB ACS880 drive indicates a control board communication error. This means there's an issue with communication between the main control board of the drive and other internal components essential for its operation

1. Check status of other converter (parameter group 6 Control and status words).
2. Check settings of parameter group 60 DDCS communication.
3. Check the corresponding settings in the control program of the other converter.
4. Check cable connections. If necessary, replace cables.