Code PRIO-493: Modbus Socket Error
Issue Description & Safety Warning
The Fanuc R-30i Series Robot Controller has triggered a critical Modbus Socket Error 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: The Modbus TCP Server was not able to open and use a TCP network socket. Remedy: This alarm generally implies that the Ethernet or TCP/IP interface is not set up correctly. For example, if no IP address is defined, then the TCP/IP stack cannot initialize. Verify network connectivity using the ping utility (on the robot, and also on the local PC).
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 PRIO-493 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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