Code ARC-091: Arc End cannot ramp to position (%s^4,%d^5)
Issue Description & Safety Warning
The Fanuc R-30i Series Robot Controller has triggered a critical Arc End cannot ramp to position (%s^4,%d^5) 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
Cause: An Arc End weld schedule specified a time of 99.0 seconds. This time value is sometimes used with Arc Starts to indicate ramping during an entire motion. This type of ramping is not available for an Arc End. A time of 99.0 seconds for an Arc End crater fill time is very long and is not recommended. If a long time is needed then 98.0 seconds will work without this error. Remedy: Use a different weld schedule for the Arc End or change the time value to a smaller value.
Source: FANUC Robot R-30iA Alarm Code List Operator's Manual
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Fanuc R-30i Series Robot Controller Alarms
Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code ARC-091 on the R-30i Series Robot Controller 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: 6553 Fanuc R-30i Series Robot Controller codes.
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