Yaskawa Sigma-7 A.810: Encoder Backup Alarm after motor replacement, what to check?
I'm getting an A.810 Encoder Backup Alarm on a Yaskawa Sigma-7 SERVOPACK after replacing a motor. The machine was down for a while, and the old motor's encoder cable was disconnected. What should I check first?
The A.810 Encoder Backup Alarm on a Yaskawa Sigma-7 SERVOPACK indicates that the absolute encoder has lost its position data due to a power supply failure. This alarm cannot be cleared with a standard alarm reset; the encoder must be re-initialized and the machine re-referenced. It often occurs after initial power-up of a new encoder, after encoder cable disconnection, or due to battery issues.
Likely causes and checks
1Encoder Cable disconnected and reconnected
- Points to it
- Disconnecting the encoder cable while the SERVOPACK control power is off will cause the absolute position data to be lost, triggering an A.810 alarm upon power-up.
- Check
- Verify the encoder connection is secure and then proceed to set up the encoder using Fn008.
2First power-up of the absolute encoder
- Points to it
- If this is a new motor or the first time this absolute encoder is being powered, it will not have any stored position data, leading to an A.810 alarm.
- Check
- Confirm it is the first power-up for this encoder and then set up (reset) the absolute encoder with Fn008.
3No power from either the SERVOPACK (+5 V) or the battery
- Points to it
- The absolute encoder requires continuous power from either the SERVOPACK or a battery to maintain position data. If both sources fail, data is lost.
- Check
- Check the battery and its connector status. If replacing the battery, ensure control power is ON, then set up the encoder.
4Absolute encoder failure
- Points to it
- If the alarm persists even after correctly setting up the encoder with a known good battery, the encoder itself may be faulty.
- Check
- Attempt to set up the encoder again. If the A.810 alarm still occurs, the Servomotor (which includes the encoder) likely needs to be replaced.
Next check: Given the motor replacement and cable disconnection, first check the encoder connection and then proceed to set up the absolute encoder using Fn008. Remember that the A.810 alarm cannot be cleared by the ALM_CLR command; it requires an absolute encoder reset.
Related questions
Describe the fault or upload a photo, and InduQT checks it against the manufacturer manuals. Share the result here when it helps someone else.