NMI Alarm in SLC (Servo LSI Controller)

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.

• 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.

Click steps to track your progress.

1. 1

   Power cycle the CNC system to attempt a reset of the SLC and clear the NMI.

2. 2

   Verify stable and clean power supply to the servo control board or the relevant section of the CNC main board.

3. 3

   Inspect the servo control board for any visible damage, such as burn marks or damaged components in the SLC area.

4. 4

   Check the servo feedback cables and motor power cables for integrity and proper shielding to rule out external electrical noise.

5. 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.