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FANUC Alarm SRVO-274 — SERVO NTED1 status abnormal

Error
Hardware
emergency stop and dual safety chains
Controllers
R-J3iB / R-30iA / R-30iB
FANUC class
SERVO
Hardware family
FANUC emergency stop, pendant and dual safety chain alarms

FANUC SRVO-274 (“SERVO NTED1 status abnormal”): NTED2 status is still ON when NTED signal is asserted First check: Repair the circuit of NTED2

Updated 2026-10-22 · LogrobotLM reference

Description

NTED2 status is still ON when NTED signal is asserted

Remedy

Repair the circuit of NTED2

Field diagnosis

Chain alarm on channel 1 of the deadman switch signal.

What to check

  • Fully release the deadman switch, then grip it again: a deadman switch held at the limit position or operated very slowly produces the code.
  • Otherwise check the NTED circuit and the teach pendant.
  • Release: emergency stop pressed/released, RES_1CH, RESET.
  • Note: Number one cause in the field: an operator who "feathers" the deadman switch.
  • Diagnostic sequence “Dual emergency stop circuit”: A chain code (230/231, 266…275, 370…373) means that only one of the two redundant channels has switched: the robot still runs, but safety is no longer redundant. Identify the channel from the number (1 = +24 V, 2 = 0 V), reproduce a firm operation of the device concerned, wait for the chain-repaired message, then RES_1CH and RESET. Never reset without having found the cause.

Related codes

SRVO-275SERVO NTED2 status abnormalSRVO-003SERVO DEADMAN switch releasedSRVO-206SYSTEM Deadman switch (SVEMG abnormal)SRVO-272SERVO SVDISC1 status abnormalSRVO-273SERVO SVDISC2 status abnormalSRVO-276SERVO Disable on T2 mode

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 →