FANUC Alarm MARL-031 — WARN … Semaphore timeout
Manufacturer wording — WARN %s Semaphore timeout
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC MARL-031 (“WARN … Semaphore timeout”): This alarm indicates that there is a problem with the serial line used for the active gripper device. First check: You must clear the serial line by changing it in the PORT I/O menu from No Use to Host Comm and then back to No Use.
Updated 2026-09-17 · LogrobotLM reference
Description
This alarm indicates that there is a problem with the serial line used for the active gripper device.
Remedy
You must clear the serial line by changing it in the PORT I/O menu from No Use to Host Comm and then back to No Use. Follow these steps:
Related codes
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 →