FANUC Alarm SRVO-278 — SYSTEM TP E-stop(SVEMG abnormal)
Error- Hardware
- emergency stop and dual safety chains
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SYSTEM
- Hardware family
- FANUC emergency stop, pendant and dual safety chain alarms
FANUC SRVO-278 (“SYSTEM TP E-stop(SVEMG abnormal)”): Status of MON1,MON2,MON3 signals are abnormal on COLD START Value shows MON1,MON2,MON3 signal status Bit 0: MON1 ON,Bit 1: MON2 ON,Bit 3: MON3 ON First check: Repair the circuit of MON1,MON2,MON3 on E.STOP unit
Updated 2026-10-22 · LogrobotLM reference
Description
Status of MON1,MON2,MON3 signals are abnormal on COLD START Value shows MON1,MON2,MON3 signal status Bit 0: MON1 ON,Bit 1: MON2 ON,Bit 3: MON3 ON
Remedy
Repair the circuit of MON1,MON2,MON3 on E.STOP unit
Field diagnosis
The teach pendant button was pressed without the emergency stop line being cut; latched version of SRVO-202.
What to check
- Release, then switch the mains power off and back on.
- If it repeats: teach pendant, teach pendant cable, then main board and emergency stop board (backup before replacement).
- Note: The teach pendant is the cause in the vast majority of cases.
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 →