Encoder Fault is one of the common faults during inverter operation. In Oulu VFDs, this fault is displayed as ERR/FU20 on the control panel.

Troubleshooting and Solutions:

1. Encoder model mismatch:
Set the correct encoder type according to the actual specifications.

2. Encoder wiring error:
Check the power supply and phase sequence of the PG card.

3. Encoder damaged:
Replace the encoder.

4. PG card abnormality:
Replace the PG card.