What causes FANUC alarm 397?

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 397?

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 397. 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 397

Fanuc 397 - Smooth interpolation parameter error

Alarm 397 occurs when the smooth interpolation (G05.1) command contains invalid parameters, incorrect syntax, or values outside the acceptable range. This is typically caused by programming errors in the Q, P, or tolerance parameters, or attempting to use smooth interpolation on a control that doesn't fully support the specified mode.

FANUCProgram/G-codeIntermediate5-30 minutes

397

Fanuc 397 - Smooth interpolation parameter error

SMOOTH INTERPOLATION PARAMETER ERROR

Root Cause Summary

Alarm 397 occurs when the smooth interpolation (G05.1) command contains invalid parameters, incorrect syntax, or values outside the acceptable range. This is typically caused by programming errors in the Q, P, or tolerance parameters, or attempting to use smooth interpolation on a control that doesn't fully support the specified mode.

Safety

Verify corrected program or parameters before resuming machining

Causes and Fixes

1
Locate the G05.1 command in the program near the alarm occurrence and verify the Q parameter is 0, 1, or 2 only.
2
Check that P parameter (if used) is within 1-10000 range and tolerance values are positive non-zero numbers.
3
Review parameter 19500-19547 (AI Contour Control/Smooth Interpolation settings) to confirm the control supports the requested mode.
Changing system parameters requires proper authorization and can affect all programs.
4
Correct the G05.1 command syntax to match control specifications or use G05.1 Q0 to disable smooth interpolation if not needed.

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