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FANUC Controller
Program/G-code · Intermediate · 5-30 minutes
Fanuc 170 - Nmi occurred
Alarm 170 NMI (Non-Maskable Interrupt) indicates a critical system-level error, typically caused by hardware failure, memory corruption, or severe electrical noise affecting the control's CPU. Unlike typical program alarms, this is a serious fault that points to control hardware issues rather than simple program formatting errors. This alarm requires immediate attention as it indicates the CPU detected an unrecoverable condition.
170
Fanuc 170 - Nmi occurred
NMI OCCURRED
Fanuc PS program alarm 170: NMI OCCURRED. This alarm is triggered by an illegal or incorrectly formatted command in the part program, or a programming condition that the Fanuc control cannot execute.
Root Cause Summary
Alarm 170 NMI (Non-Maskable Interrupt) indicates a critical system-level error, typically caused by hardware failure, memory corruption, or severe electrical noise affecting the control's CPU. Unlike typical program alarms, this is a serious fault that points to control hardware issues rather than simple program formatting errors. This alarm requires immediate attention as it indicates the CPU detected an unrecoverable condition.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Power cycle the control completely and observe if alarm returns immediately or during specific operations.
Record all position data and program backups before power cycling
- 2
Check battery voltage on CPU board - low battery can cause memory corruption leading to NMI errors. Replace if voltage is below 3.0V.
Battery replacement requires proper backup procedure to prevent data loss
- 3
Reseat all board connections on main CPU, FROM board, and memory modules. Check for corrosion or damaged connectors.
Use proper ESD precautions when handling control boards
- 4
If alarm persists, replace the main CPU board or mother board as hardware failure is likely. Contact Fanuc for board diagnostics and replacement.
Ensure you have complete system backup before board replacement
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