FANUC Alarm SRVO-022 — SERVO SRDY on
Error- Hardware
- servo amplifier
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO
Manufacturer wording — SERVO SRDY on (Group:%d Axis:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-022 (“SERVO SRDY on”): SRDY was already on when an attempt was made to turn on the MCC with HRDY. First check: WARNING: Before you continue to the next step, perform a complete controller backup to save all of your programs and settings from memory for this robot. Likely part: Servo amplifier (Servo amplifier) +2 more.
Updated 2026-10-22 · LogrobotLM reference
Description
SRDY was already on when an attempt was made to turn on the MCC with HRDY. HRDY is the signal sent from the host to the servo system to specify whether to turn the servo amplifier's MCC on or off. SRDY is the signal sent from the servo system to the host to indicate whether a servo amplifier's MCC is on or off.
Remedy
WARNING: Before you continue to the next step, perform a complete controller backup to save all of your programs and settings from memory for this robot. After you complete the next step, restore the saved data to the new Main CPU board if memory has been lost. Otherwise, you could injure personnel, damage equipment, or lose data. 1. Verify that the battery is connected to the Main CPU board before removing the Main CPU board. Replace the axis control card on the Main CPU board. 2. Replace the servo amplifier. 3. If this does not clear the alarm, verify that all connectors are securely connected.
Field diagnosis
When the amplifier contactor was about to close, its "ready" feedback was already active: stuck contact or false feedback.
What to check
- Replace the designated amplifier; then the corresponding servo board (or auxiliary axis board).
- Note: Amplifier contactor with welded contacts: to be treated as a safety fault.
Part to check / replace
FANUC SRVO-022 points to the hardware below — start here before ordering.
Tap a part for every code that points to it — and verify the exact variant for your controller before ordering.
Related codes
Same hardware involved
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 →