A.81Alarm · Encoder / feedback
Yaskawa SGDH A.81: Encoder Backup Error
What A.81 means
All power to the absolute encoder was lost, so its stored position data was cleared.
Symptoms
Alarm at power-on, often after a battery change or a disconnected cable.
Is it repairable?
Usually a battery or setup issue; repairable when the encoder has failed.
Common causes
- Backup battery dead or removed while power was off
- Encoder cable disconnected
- Failed encoder
Safe checks
- 1Replace the backup battery with power on
- 2Set up the absolute encoder again
- 3If it returns, check the encoder
Drives hold dangerous voltage after power-off. Checks should only be done by qualified personnel, with power isolated and the DC link discharged.
Reviewed by AutomIQ repair technicians. Code and name from the Yaskawa SGDH SERVOPACK manual.
Related Yaskawa SGDH faults
- A.10Overcurrent or Heat Sink Overheated
- A.30Regeneration Error Detected
- A.40Overvoltage
- A.41Undervoltage
- A.71Overload: High Load
- A.C9Encoder Communications Error