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FANUC Controller
Servo/Axis · Intermediate · 5-30 minutes
Fanuc 479 - Fssb servo amp mismatch
Alarm 479 indicates a mismatch between the servo amplifier configuration stored in the CNC parameters and the actual amplifiers detected on the FSSB network. This typically occurs after amplifier replacement, parameter changes, or when amplifiers are swapped between axis positions without updating the system configuration.
479
Fanuc 479 - Fssb servo amp mismatch
FSSB SERVO AMP MISMATCH
An FSSB (Fanuc Serial Servo Bus) error has been detected related to fssb servo amp mismatch. The serial bus communication between the CNC and servo amplifiers is affected.
Root Cause Summary
Alarm 479 indicates a mismatch between the servo amplifier configuration stored in the CNC parameters and the actual amplifiers detected on the FSSB network. This typically occurs after amplifier replacement, parameter changes, or when amplifiers are swapped between axis positions without updating the system configuration.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Check maintenance records to confirm if any servo amplifiers were recently replaced or serviced.
- 2
Access diagnostic screen and verify the amplifier model numbers detected on FSSB against parameter 1815 (amplifier type) for each axis.
- 3
Compare the physical amplifier labels with the CNC parameter settings to identify which axis has the mismatch.
- 4
Update parameter 1815 for the affected axis to match the installed amplifier model, or replace the amplifier with the correct model per original specifications.
CAUTION: Incorrect parameter settings can cause servo runaways. Verify all amplifier parameters before enabling servos.
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