4690

Common Causes

• Faulty rotary encoder 1 or the motor encoder
• Encoder link cable or connector fault
• Problem on the control base of the inverter unit
• Encoder power or communication handshake failure at power-up

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XXYYZZZZ = Initialization failure detail; same format as alarm 0865 'MCS Encoder initialize failed'.
2. 2Record the XXYYZZZZ code shown on the alarm screen and decode it against the alarm 0865 'MCS Encoder initialize failed' format to see at which initialization step the encoder failed.
3. 3Inspect the encoder link cable and its connectors between rotary encoder 1 / the motor encoder and the inverter unit for bent pins, oil or damage, and reseat both ends.
4. 4Swap the encoder link cable with a known-good cable to isolate a wiring fault before condemning hardware.
5. 5If the failure persists, substitute the motor encoder or rotary encoder 1 with a known-good unit to confirm the encoder as the cause.
6. 6When encoder and cable are eliminated, the fault lies on the control base of the inverter unit; have that board inspected or exchanged, then power up and home the axis.