Cause : Memory unit detached comes when the memory unit was detached when the control unit was powered.

The fault code 64B0 in your ABB ACS880 drive indicates a memory unit detached issue. This means the drive has detected that the memory unit, which stores important files and data for operation, is not properly connected.

1. Switch off the power to the control unit and reinstall the memory unit.
2. In case the memory unit was not actually removed when the fault occurred, check that the memory unit is properly inserted into its connector and its mounting screw is tight.
3. Reboot the control unit (using parameter 96.8 Control board boot) or by cycling power.