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FANUC Alarm ARC-056 — Invalid sync

Manufacturer wording — Invalid sync (%s^4,%d^5)
The manual prints placeholders; your controller fills them in with the real group, axis or number.

FANUC ARC-056 (“Invalid sync”): An Arc Start instruction specified synchronizing with an Equipment that is not also synchronized. First check: Check the synchronization equipment number specified in the Arc instruction or in the specified weld schedule SYNCDT detail menu.

Updated 2026-09-17 · LogrobotLM reference

Description

An Arc Start instruction specified synchronizing with an Equipment that is not also synchronized.

Remedy

Check the synchronization equipment number specified in the Arc instruction or in the specified weld schedule SYNCDT detail menu. Refer to the Arc Start Synchronization section in the FANUC ArcTool Operator's Manual.

Related codes

ARC-054STOP No motion while arc weldingARC-055No sync EqARC-057Cannot ramp t1=… > t2=…ARC-058Wire stick is still detected

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →