Code ER27: LADDER FUNC. PRM IS OUT OF RANGE
Issue Description & Safety Warning
The Fanuc 30i/31i/32i CNC has triggered a critical LADDER FUNC. PRM IS OUT OF RANGE 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
Correct the sequence program; change the parameter number specif ied in a functional instruction to a value that is within the allowable range. An out-of-range parameter number is specified in the TMR, TMRB, TMRBF, CTR, CTRB, DIFU, or DIFD functional instruction.
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 ER27 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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