Robotics in Manufacturing
SRVO-204

SRVO-204: External (SVEMG abnormal) E-stop

A safety-circuit self-consistency failure: the external E-stop button was pressed, but the emergency stop line did NOT disconnect as it must.

What it means

A safety-circuit self-consistency failure: the external E-stop button was pressed, but the emergency stop line did NOT disconnect as it must. The stop function itself is suspect - treat as a serious electrical fault, not a nuisance.

Common causes

Ranked by what technicians most often find, most likely first.

  1. Fault in the E-stop line's related parts - wiring, board, or unit - preventing the line from opening when commanded.

How to fix it

  1. Do not keep operating around this alarm: an E-stop that doesn't drop the line is a failed safety function.
  2. Diagnosis per the Controller Maintenance Manual, qualified personnel, lockout/tagout. Power-cycle required to clear - but clearing it is not fixing it.

Quick facts

Category
System
Affected series
R-30iB; R-30iB Mate; R-30iB Plus; R-30iB Mate Plus
Alarm family
SRVO

Verified against FANUC documentation (B-83284EN-1).Last reviewed: 2026-07-09.Editorial process