Code WN68: I/O CONFIGURATION DATA IS NOT WRITTEN TO FLASH ROM
Issue Description & Safety Warning
The Fanuc 30i/31i/32i CNC has triggered a critical I/O CONFIGURATION DATA IS NOT WRITTEN TO FLASH ROM alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
If you want to use changed I/O configuration data again next time you power on the system, write the I/O configuration data to flash ROM. You have changed I/O configuration data using the I/O c onfiguration data editing or DATA I/O screen, but you have not yet written the changed I/O configuration data to flash ROM. If you shut down the system without writing the changed I/O configuration data to flash ROM, the changes you have made will be nowhere next time you turn on the power.
Source: Fanuc Series 30i/31i/32i-A Maintenance Manual, Appendix A Alarm List — PMC alarms (B-64485EN/01)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc 30i/31i/32i CNC Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code WN68 on the 30i/31i/32i CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 85 Fanuc 30i/31i/32i CNC codes.
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