RAM Parity Error

What does 911 mean?

These alarms indicate a parity error has been detected in the Random Access Memory (RAM) of the Fanuc Series 20 CNC. This means that data being read from or written to RAM is corrupted, leading to unstable operation, data loss, or system crashes.

• Faulty RAM module(s) on the CNC main board or memory expansion board.
• Transient power fluctuation or electrical noise affecting memory operations.
• Physical damage to the CNC main board or memory components.
• Incorrect memory timing or configuration.
• Electrostatic discharge (ESD) damage during handling or installation.

Click steps to track your progress.

1. 1

   Power cycle the CNC system completely to clear any transient memory errors.

2. 2

   Verify stable and clean power supply to the CNC main unit, checking for voltage sags or spikes.

3. 3

   Inspect the CNC main board and any memory expansion modules for proper seating, visible damage, or corrosion.

4. 4

   If possible, reseat the RAM modules. If the system has multiple RAM modules, try operating with one module at a time to identify the faulty one.

5. 5

   If the alarm persists, it often indicates a faulty CNC main board or RAM module that requires replacement.