SRVO-021: SRDY off
The servo amplifier for the named group/axis never reported ready - the contactor that powers the drives didn't close when commanded.
What it means
The servo amplifier for the named group/axis never reported ready - the contactor that powers the drives didn't close when commanded. Usually a symptom, not the disease: check what other alarm fired with it.
Common causes
Ranked by what technicians most often find, most likely first.
- Another alarm occurred simultaneously and is the real cause - check alarm history first.
- Wrong setup after adding or changing an auxiliary axis (FSSB line, start axis, amplifier number or type).
- Machine lock left on in a multi-group system.
- Robot disconnect switch misconfiguration ($ROBOT_ISOLC) on auxiliary axes, or a failed disconnect switch unit.
- Hardware: amplifier, E-stop unit, or wiring.
How to fix it
- Open the alarm history and chase any alarm that fired alongside this one - fix that and SRVO-021 usually follows.
- If it started right after auxiliary-axis changes, re-verify FSSB line number, hardware start axis, amplifier number and type.
- Check machine lock status on multi-group systems and disconnect switch settings.
- Only then go hardware-hunting per the maintenance manual.
Quick facts
- Category
- Servo
- Affected series
- R-30iB; R-30iB Mate; R-30iB Plus; R-30iB Mate Plus
- Alarm family
- SRVO