Having issues with Alarm Display: A.C90 A.C91. Alarm Name: Encoder Communications Error & Encoder Communications Position Data Error on Sony SI-F209 Electronic Part Mounter? Read our step-by-step SMT maintenance solution below. If you require replacement feeders, nozzles, or sensors, contact SMTBOX for OEM-compatible parts.
Alarm Display: A.C90 A.C91
Alarm Name: Encoder Communications Error & Encoder Communications Position Data Error
Situation at Alarm Occurrence: Occurred when the control power supply was turned ON or during operation.
Cause: The encoder wiring and the contact are incorrect.
Corrective Actions: Correct the encoder wiring.
Cause: Noise interference occurred due to incorrect encoder cable specifications.
Corrective Actions: Use tinned annealed copper twisted-pair or twisted-pair shielded wire with a core of at least 0.12 mm2 (0.0002 in2)
Cause: Noise interference occurred because the wiring distance for the encoder cable is too long.
Corrective Actions: The wiring distance must be 20m (65.6 ft) max.
Cause: The noise interference occurred on the signal line because the encoder cable is bent and the sheath is damaged.
Corrective Actions: Correct the encoder cable layout.
Cause: The encoder cable is bundled with a high-current line or near a high-current line.
Corrective Actions: Correct the encoder cable layout so that no surge is applied.
Cause: The FG varies because of the influence from machines on the servomotor side, such as welder.
Corrective Actions: Make the grounding for the machine separately from PG side FG.
Our editorial team consists of senior SREs, mechanical engineers, and SMT assembly specialists with over 15 years of industry experience in PCB assembly line optimization. All technical articles are reviewed and verified for mechanical and electronic compatibility before publication.