NMI Alarm in SLC (Servo LSI Controller)
Fanuc · Series 20 CNC
What does 971 mean?
This alarm indicates a Non-Maskable Interrupt (NMI) originating from the Servo LSI Controller (SLC) within the Fanuc Series 20 CNC. The SLC is responsible for critical servo control functions, so an NMI here signifies a severe hardware malfunction in the servo control circuitry, causing the system to halt.
Common Causes
- Faulty SLC chip or associated servo control circuitry on the CNC main board or servo control board.
- Memory error within the SLC or related components.
- Power supply irregularities affecting the SLC.
- Excessive electrical noise impacting the SLC.
- Physical damage to the SLC or its board.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Power cycle the CNC system to attempt a reset of the SLC and clear the NMI.
- 2
Verify stable and clean power supply to the servo control board or the relevant section of the CNC main board.
- 3
Inspect the servo control board for any visible damage, such as burn marks or damaged components in the SLC area.
- 4
Check the servo feedback cables and motor power cables for integrity and proper shielding to rule out external electrical noise.
- 5
If the alarm persists, it indicates a hardware fault on the CNC main board or servo control board related to the SLC, requiring replacement.