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FANUC Controller
Program/G-code · Intermediate · 5-30 minutes
Fanuc 166 - Illegal use of g69
Alarm 166 occurs when G69 (coordinate system rotation cancel) is used without a preceding G68 (coordinate system rotation command), or when G69 is called while no rotation is active. This alarm can also trigger if G69 is used in an incompatible mode or with incorrect syntax for the specific control configuration.
166
Fanuc 166 - Illegal use of g69
ILLEGAL USE OF G69
Fanuc PS program alarm 166: ILLEGAL USE OF G69. 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
Alarm 166 occurs when G69 (coordinate system rotation cancel) is used without a preceding G68 (coordinate system rotation command), or when G69 is called while no rotation is active. This alarm can also trigger if G69 is used in an incompatible mode or with incorrect syntax for the specific control configuration.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Review the part program from the beginning and search for all instances of G68 and G69 commands to verify proper pairing.
- 2
Check if a G69 appears before any G68 command, or if there are multiple G69 commands following a single G68.
- 3
Verify that any subprograms or loops maintain proper G68/G69 nesting and that rotation is active when G69 is called.
- 4
If G69 is unnecessary, remove it from the program. If rotation is needed, add the corresponding G68 command with proper syntax (G68 X_ Y_ R_ or G68 G17-G19 X_ Y_ Z_ R_ depending on control generation).
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