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  1. Home
  2. Fault Codes
  3. Yaskawa SGDH
  4. A.C9
A.C9Alarm · Encoder / feedbackUsually repairable

Yaskawa SGDH A.C9: Encoder Communications Error

What A.C9 means

The SERVOPACK cannot communicate with the motor's serial encoder.

Symptoms

Alarm at power-on or intermittently while moving.

Is it repairable?

Yes: encoder replacement and SERVOPACK interface repair.

Common causes

  • Encoder cable damaged or disconnected
  • Noise on the encoder cable
  • Failed encoder
  • Faulty encoder interface in the SERVOPACK

Safe checks

  1. 1Inspect the encoder cable and connector
  2. 2Check shield grounding
  3. 3Try a known-good cable

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.81Encoder Backup Error
All 49 Yaskawa SGDH codes

Still showing A.C9?

SGDH SERVOPACK showing an alarm?

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Related services: Encoder repair · Servo motor repair · Servo drive repair

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