What causes FANUC alarm 336?

A second G43 or G44 tool length compensation command was programmed on a different axis before canceling the first with G49. The programmer attempted to apply tool length compensation C to more than one axis simultaneously without canceling the previous offset first. A subprogram or macro call applies tool length compensation on an axis that already has an active offset from the main program. Copy-paste programming errors where a G43 block was duplicated or misplaced, creating two active compensation commands on different axes. Post-processor output incorrectly generating multiple tool length compensation commands across axis changes without inserting G49 cancel blocks.

How do I fix FANUC alarm 336?

1. Search the active CNC program for all G43 and G44 commands and verify that each one is preceded by a G49 cancel if a previous compensation was already active on a different axis. 2. Check that every tool change sequence follows the correct order: G49 to cancel existing offset, then G43 or G44 with the new tool and H offset value on the intended axis. 3. If subprograms or macros are used, trace through the full call stack to confirm no tool length compensation is left active when returning to the main program and re-applying compensation. 4. Review the post-processor settings if the program was CAM-generated, ensuring it outputs G49 before any new G43 or G44 block that targets a different axis. 5. Correct the program by inserting G49 at the appropriate location before the offending G43 or G44 command, then restart the program from a safe position. 6. After editing, perform a dry run with single block mode and feed hold to step through the tool compensation blocks and confirm no alarm recurs before running the full cycle.

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FANUC Controller

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

Alarm 336

Fanuc Alarm 336 - TOOL COMPENSATION COMMANDED MORE THAN TWO AXES

Fanuc Alarm 336 occurs when tool length compensation (G43/G44) is commanded on more than two axes simultaneously, or when attempting to change the compensation axis without first canceling the existing offset with G49. This alarm is triggered by the CNC detecting multiple active tool length offsets that violate the system's compensation axis limitations.

FANUCProgram/G-codeBasic15-30 minutes

336

Fanuc Alarm 336 - TOOL COMPENSATION COMMANDED MORE THAN TWO AXES

TOOL LENGTH OFFSET C AXIS ERROR

Root Cause Summary

Fanuc Alarm 336 occurs when tool length compensation (G43/G44) is commanded on more than two axes simultaneously, or when attempting to change the compensation axis without first canceling the existing offset with G49. This alarm is triggered by the CNC detecting multiple active tool length offsets that violate the system's compensation axis limitations.

Causes and Fixes

1
Review the program block where alarm 336 occurred. Check the PROGRAM display screen and note the N-number and line content where execution stopped.
2
Verify if G43 or G44 was previously commanded on one axis (typically Z) and is now being commanded on a different axis without G49 cancellation between them.
3
Insert G49 (tool length compensation cancel) in the program block immediately before commanding the new tool length compensation axis. Example: N100 G49; N110 G43 H__ Y__;
4
Reset the alarm using RESET button, return to program start or safe position, and re-execute the corrected program to verify proper compensation axis switching.
Ensure tool is clear of workpiece before program restart to prevent collision

DIY Feasiblehigh confidence

Call a technician if:

·Parameter 5006 changes required
·Custom macro modification needed
·PMC ladder logic issues

Prevention

Always use G49 before changing tool length compensation axes
Structure subprograms to be compensation-neutral
Implement consistent tool change procedures with proper G49 cancellation

Common Mistakes

Assuming G43 automatically cancels previous compensation
Not checking subprogram compensation inheritance
Modifying parameters without understanding machine configuration

Related Alarms

335 337 501

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