Code SRVO-021: SRDY off (Group:%d Axis:%d)
Issue Description & Safety Warning
The Fanuc R-30i Series Robot Controller has triggered a critical SRDY off (Group:%d Axis:%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: The ready signal of the servo amplifier corresponding to the displayed group and axis was turned off. Remedy: 1. Refer to those cause/measures when the alarm history is confirmed and other alarms have occurred at the same time. 2. If this alarm occurred after add axis or modification of axis' setup, confirm whether a set content is correct. If the mistake is found, modify it. Especially, confirm whether to find the mistake in the hardware start axis number, the amplifier number, and the amplifier type. Note: In the axis setting to the multi-axis amplifier (It is one amplifier that has more than two axes), set it as an amplifier number different in each axis. 3. Confirm the setting of the machine lock for the multi group. • Advance to measures 4 when all motion groups machine lock are released. • Release the machine lock of the robot when the robot (six axis amplifier) is a machine lock. Note: When six axis amplifier is made a machine lock, the amplifier subordinate to this turns off and SRDY is turned off. • In the multi axis amplifier case, set the machine lock the same value with the axes allocated to this amplifier mutually. For instance, when G2-J1 and G3-J1 are allocated to a common two-axis amplifier, the setting of the machine lock of G2 and G3 should be the same. 4. If this alarm cannot be reset, refer to the Controller Maintenance Manual for more information. Note: There is a possibility when the specification of the teach pendant is not correct compared with the controller. For instance, when the teach pendant of the RIA/CE specification is used in the controller of non-RIA/CE specification, this alarm might occur. Connect the correct teach pendant corresponding to the controller.
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 SRVO-021 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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