What causes FANUC alarm 088?

Part program contains an illegal G-code or M-code combination for this alarm type. Missing or incorrect address word in the program block. Axis or parameter value out of range for the commanded function. Required option not enabled on this CNC for the commanded function. Conflict between active modal states and the commanded function.

How do I fix FANUC alarm 088?

1. Note the block number shown on the alarm screen and locate that block in the program. 2. Review the command in that block against the Fanuc programming manual for alarm 88. 3. Check for missing address words, incorrect values, or conflicting G-code combinations. 4. Verify any required CNC options are enabled if using advanced functions. 5. Correct the program and verify the fix before restarting machining.

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FANUC Controller

Tool Changer · Intermediate · 5-30 minutes

Alarm 088

Fanuc 88 - Cannot use atc with compensation

Alarm 88 occurs when the part program attempts to execute an automatic tool change (M06 or similar ATC command) while cutter radius compensation (G41/G42) or tool length compensation offset mode is still active. The Fanuc control requires all compensation modes to be canceled (G40 for cutter comp) before performing a tool change to prevent potential collisions and calculation errors.

FANUCTool ChangerIntermediate5-30 minutes

088

Fanuc 88 - Cannot use atc with compensation

CANNOT USE ATC WITH COMPENSATION

Root Cause Summary

Alarm 88 occurs when the part program attempts to execute an automatic tool change (M06 or similar ATC command) while cutter radius compensation (G41/G42) or tool length compensation offset mode is still active. The Fanuc control requires all compensation modes to be canceled (G40 for cutter comp) before performing a tool change to prevent potential collisions and calculation errors.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Search the program backward from the alarm line to locate the last G41 or G42 command that activated cutter compensation.
2
Insert a G40 (cancel cutter compensation) command on a separate line before the M06 tool change command.
Ensure G40 is executed with a linear move (G01) to properly exit compensation mode, not just issued alone.
3
Verify that the G40 move does not create a collision or gouging condition when exiting compensation.
4
Re-run the program in single block mode to confirm the tool change executes without alarm.

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