SRVO-222: Lack of Amp
At power-up, the controller couldn't find the servo amplifier for the named group/axis.
What it means
At power-up, the controller couldn't find the servo amplifier for the named group/axis. The diagnosis walks from 'is it even powered' through a clever ground-fault isolation test to configuration and hardware.
Common causes
Ranked by what technicians most often find, most likely first.
- No power to the amplifier - dark LEDs, loose connectors on the amplifier or E-stop unit.
- Ground-faulted pulse coder cable (amplifier LED may blink '-').
- Wrong-generation hardware: an R-30iA aux amplifier on an R-30iB controller.
- Software axis config (FSSB line, hardware start axis).
- Hardware: aux amplifier, 6-axis amplifier, optical fiber cable, servo/aux axis card.
How to fix it
- If no amplifier LEDs light with the controller on, chase power. With the controller de-energized and locked out, reseat every connector on the amplifier and the E-stop unit.
- Isolation test: with the controller de-energized and locked out, disconnect the pulse coder cables JF1 and JF2 from the amplifier. Restore power, and if the alarm clears, the pulse coder cable has a ground fault. Replace that cable with the controller de-energized and locked out again.
- Confirm the amplifier generation matches the controller.
- Verify the FSSB line and the hardware start axis numbers.
- Then replace hardware in order, each with the controller de-energized and locked out: amplifiers, optical fiber, then servo card.