What causes FANUC alarm 395?

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 395?

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 395. 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

Program/G-code · Intermediate · 5-30 minutes

Alarm 395

Fanuc 395 - Illegal command in smooth interpolation

Alarm 395 occurs when the Fanuc control detects an incompatible or improperly formatted command within a smooth interpolation (G05.1 Q1 or AI Contour Control) block. The control cannot execute certain commands like tool changes, canned cycles, or coordinate system changes while smooth interpolation mode is active. This is a programming error that requires modification of the part program structure.

FANUCProgram/G-codeIntermediate5-30 minutes

395

Fanuc 395 - Illegal command in smooth interpolation

ILLEGAL COMMAND IN SMOOTH INTERPOLATION

Root Cause Summary

Alarm 395 occurs when the Fanuc control detects an incompatible or improperly formatted command within a smooth interpolation (G05.1 Q1 or AI Contour Control) block. The control cannot execute certain commands like tool changes, canned cycles, or coordinate system changes while smooth interpolation mode is active. This is a programming error that requires modification of the part program structure.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Search the program for G05.1 Q1 activation code and identify where it is cancelled (G05.1 Q0 or G05 P0).
2
Review all commands between the smooth interpolation activation and cancellation blocks for prohibited functions (M06, G28, G30, G54-G59, G65, G66, G73-G89, G04).
3
Cancel smooth interpolation with G05.1 Q0 before the prohibited command, then reactivate G05.1 Q1 after the command if needed.
Ensure modal settings (feed rate, spindle speed, coordinate system) are properly established before reactivating smooth interpolation.
4
Verify the modified program in single block or machine lock mode to confirm alarm is cleared.

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