Robotics in Manufacturing
SRVO-044

SRVO-044: DCHVAL alarm (DC link overvoltage)

The DC bus voltage inside the servo power circuit went abnormally high.

What it means

The DC bus voltage inside the servo power circuit went abnormally high. Posts against the amplifier (axes 1-2 or 1-2-3). Power-cycle to clear; if it comes back, this is a power-electronics diagnosis, not a pendant fix.

Common causes

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

  1. Regenerative energy spiking the DC link (heavy decel, vertical axes).
  2. Incoming supply voltage high or unstable.
  3. Amplifier or power supply unit fault.

How to fix it

  1. Cycle power and observe.
  2. Check incoming supply voltage against controller spec, including under plant load swings.
  3. Recurrence sends you to the controller maintenance manual's power circuit diagnosis - qualified personnel, lockout/tagout, and respect for the DC bus capacitors, which hold charge after power-off.

Quick facts

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

Related codes

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