LogrobotLM

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FANUC Alarm ARC-120 — Enable/Disable Sim mode failed

FANUC ARC-120 (“Enable/Disable Sim mode failed”): The necessary signals for Simulation mode cannot be detected. First check: Verify that AI/O and WDI/O signals are assigned appropriately.

Updated 2026-09-17 · LogrobotLM reference

Description

The necessary signals for Simulation mode cannot be detected.

Remedy

Verify that AI/O and WDI/O signals are assigned appropriately.

Related codes

ARC-106WARN Config of Roboweld is invalidARC-107STOPL Roboweld internal ErrorARC-121Weld not performed(Sim mode)ARC-122Cannot SIM/UNSIM

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 →