KRC0985

Common Causes

• Attempting to assign a new value to a system-reserved signal variable in KRL code
• Using an assignment operator on a predefined input or output signal
• Incorrectly declaring a variable with the same name as a protected predefined signal
• KRL program contains legacy code attempting to modify signals that became protected in newer KRC versions
• Signal configuration conflict where a signal is simultaneously defined as both user-modifiable and system-protected

Troubleshooting Steps

1. 1Review the KRL program source code and identify the line attempting to modify the predefined signal referenced in parameter @P1@
2. 2Consult KUKA documentation to confirm whether the signal is predefined and protected from user modification
3. 3Remove or comment out the assignment statement that modifies the protected signal
4. 4If signal modification is required for application logic, use an intermediate variable instead and map it appropriately in the signal configuration
5. 5Verify the signal names in the KRL code do not conflict with KUKA reserved system signals (check $signal definitions)
6. 6Recompile and test the corrected KRL program, then clear the alarm and restart the KRC