LogrobotLM

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FANUC Alarm HOST-100 — WARN Communications error

Warning
Hardware
main board and memory
Controllers
R-J3iB / R-30iA
FANUC class
WARN
Hardware family
FANUC teach pendant, main board, CMOS and controller battery alarms

FANUC HOST-100 (“WARN Communications error”): The protocol format was invalid. First check: Verify protocol field in the setup menu and retry the operation.

Updated 2026-10-22 · LogrobotLM reference

Description

The protocol format was invalid.

Remedy

Verify protocol field in the setup menu and retry the operation.

Field diagnosis

The protocol format configured on the port is invalid.

What to check

  • Check the protocol field in the port setup menu and try again.
  • Note: Configuration fault, not hardware; listed because of its proximity to the serial ports.

Related codes

HOST-111WARN Cycle power to use EthernetMEMO-113WARN File access errorHOST-006WARN End of file reachedHOST-008WARN Only one file may be openedHOST-101WARN Directory read errorHOST-102WARN Block check error

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 →