Code MOTN-209: Modify Singular Dest(L:%d)
Issue Description & Safety Warning
The Fanuc R-30i Series Robot Controller has triggered a critical Modify Singular Dest(L:%d) 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: This warning message indicates that the taught position at the specific line is inside a singularity zone. By default, the system modifies it in order to control the rotation of axis 4. If $ra_prarmgrp[].$use_strt_j4 = TRUE, the Auto 4.ERROR CODES B-83124EN-6/02 Singularity Avoidance function will internally modify the destination position when it is inside a pre-defined singularity zone in the following way: z The joint angle of Axis 4 is kept the same as the value of the previous position z The TCP location (x, y and z) of the position is the same as it was taught (no location error) z The orientation (w, p and r) of the position is kept as close to the taught position as possible (minimal orientation error) This warning message is posted only when the program motion is executed under T1/T2 mode and $ra_paramgrp[].$warnmessenb = TRUE. Remedy: If you do not want the system to modify the singularity point, set $ra_paramgrp[].$use_strt_j4 = FALSE.
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 MOTN-209 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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