What causes FANUC alarm 031?

Incorrect or missing P address in G10 command. Attempting to use G10 without specifying a valid L number. Trying to set a parameter or value that is out of the valid range.

How do I fix FANUC alarm 031?

1. Check the G-code program and locate the G10 command that is triggering the alarm. Ensure the P address is specified correctly and matches the intended function. 2. Verify the L number used with G10 is a valid value, such as L2 for setting work coordinate system offsets. 3. Review the parameter or value you are attempting to set with G10 and confirm it is within the allowed range for that control feature. 4. If the issue persists, try breaking the G10 command into multiple steps to isolate the problem, such as setting each offset individually. 5. Consult the Fanuc programming manual for detailed G10 syntax requirements and limitations for your specific control model. 6. As a last resort, try uploading a backup of the program and reloading it to the CNC to rule out any corruption in the file.

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FANUC Controller

Program/G-code · Intermediate · 15-30 minutes

Alarm 031

Fanuc Alarm 031 - ILLEGAL P COMMAND IN G10

Fanuc Alarm 031 occurs when a G10 programmable data setting command is issued with an invalid, missing, or out-of-range address specification (typically P, R, or Q) for the selected L-code function. This alarm also triggers when the corresponding parameter that enables the L-code function is not set correctly, preventing the system from accepting the data input command.

FANUCProgram/G-codeIntermediate15-30 minutes

031

Fanuc Alarm 031 - ILLEGAL P COMMAND IN G10

FANUC ALARM 31

Root Cause Summary

Fanuc Alarm 031 occurs when a G10 programmable data setting command is issued with an invalid, missing, or out-of-range address specification (typically P, R, or Q) for the selected L-code function. This alarm also triggers when the corresponding parameter that enables the L-code function is not set correctly, preventing the system from accepting the data input command.

Causes and Fixes

1
Review the active G10 block in the program at the alarm point. Check the exact G10 L-code being used (L2 for work offset, L10/L11 for tool offset, L20 for additional work offset, etc.).
2
Verify the P address value is within valid range: For G10 L2, P must be 1-6 (G54-G59) or extended range if parameter 1220 bit 5 (EWZ) is enabled (P1-300+). For G10 L10/L11, P must match valid tool number range per parameter 6800 (maximum tool number).
3
Check that all required addresses for the L-code are present. Example: G10 L2 P_ X_ Y_ Z_ requires P to specify work offset number. If using R address (G10 L20), verify parameter 6004#1 (R designation) is set to 1.
4
Correct the program syntax with valid address and value. Example: Change 'G10 L2 X100.0 Y50.0' to 'G10 L2 P1 X100.0 Y50.0' to specify G54 work offset.

DIY Feasiblehigh confidence

Call a technician if:

·Parameter changes require machine builder approval
·G10 function needs to be enabled but safety concerns exist
·Macro option installation required

Prevention

Always verify P address ranges before programming G10 commands
Use OFFSET display to confirm valid offset numbers
Test G10 commands in single block mode first
Document which G10 functions are enabled on each machine

Common Mistakes

Using P0 with L codes that don't support it
Forgetting to enable parameter 3202 bits
Mixing up coordinate system numbers (P1=G54, not G53)
Using tool numbers beyond parameter 6001 limit

Related Alarms

030 032 033 010 011

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