A.C91 fault in Yaskawa Sigma 5 servo drive

Categories: Faults & Alarm

A.C91 Encoder Communications Position Data Error fault in Yaskawa Sigma 5 servo drive

Cause:

  • Noise on I/O signal line (bent cables/damaged sheaths).
  • Linear scale cables bundled with high-current lines.
  • FG potential varies due to other machines (e.g., welders).

Remedy:

  • Check cable layout and connectors.
  • Confirm there is no surge voltage; separate cables.
  • Properly ground machines to separate from the linear scale FG.