axismd.ai
FANUC Controller
Program/G-code · Intermediate · 5-30 minutes
Fanuc 165 - Illegal use of g68
G68 is the coordinate rotation command that requires specific modal conditions and parameter settings to function correctly. This alarm occurs when G68 is programmed without proper setup, in an incompatible mode, or with incorrect syntax that violates the control's execution rules.
165
Fanuc 165 - Illegal use of g68
ILLEGAL USE OF G68
Fanuc PS program alarm 165: ILLEGAL USE OF G68. This alarm is triggered by an illegal or incorrectly formatted command in the part program, or a programming condition that the Fanuc control cannot execute.
Root Cause Summary
G68 is the coordinate rotation command that requires specific modal conditions and parameter settings to function correctly. This alarm occurs when G68 is programmed without proper setup, in an incompatible mode, or with incorrect syntax that violates the control's execution rules.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Check that a plane selection code (G17, G18, or G19) is active before the G68 command in the program.
- 2
Verify that tool radius compensation (G41/G42) is cancelled with G40 before executing G68.
- 3
Ensure no canned cycles (G73-G89) are active when G68 is called. Cancel with G80 if necessary.
- 4
Confirm the rotation center coordinates (X, Y, or Z values) are specified in absolute mode (G90), not incremental (G91).
Seeing Multiple Alarms?
Seeing another alarm with this one? Enter the code.
Get machine-aware diagnosis
AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.
Start freeWas this guide helpful?
Always verify with your machine manual or a certified technician before performing service procedures.