What causes FANUC alarm 349?

Machine system or function indicated by the alarm name has detected a fault. Control parameter or configuration error related to the alarm condition. Hardware component fault on the CNC or machine. Part program error or illegal operation for the indicated function. Machine interlock or safety condition not satisfied.

How do I fix FANUC alarm 349?

1. Note the alarm number and check the Fanuc alarm screen for any sub-code or additional details. 2. Identify the specific machine system or function from the alarm name. 3. Power cycle the machine to clear transient faults. 4. Consult the Fanuc parameter or operator manual for alarm 349 specific remedy. 5. Contact Fanuc service if the alarm persists after basic troubleshooting.

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FANUC Controller

Program/G-code · Intermediate · 30-60 minutes

Alarm 349

Fanuc Alarm 349 - TOOL CHANGE SPINDLE NOT STOP

Fanuc Alarm 349 occurs when the CNC attempts to execute a tool change command (M06 or automatic tool change) while the spindle is still rotating. The system expects spindle speed to reach zero (S=0) and spindle orientation complete before allowing tool changer operations. This is a safety interlock to prevent tool damage or crash during ATC sequences.

FANUCProgram/G-codeIntermediate30-60 minutes

349

Fanuc Alarm 349 - TOOL CHANGE SPINDLE NOT STOP

SYSTEM ALARM 349

Root Cause Summary

Fanuc Alarm 349 occurs when the CNC attempts to execute a tool change command (M06 or automatic tool change) while the spindle is still rotating. The system expects spindle speed to reach zero (S=0) and spindle orientation complete before allowing tool changer operations. This is a safety interlock to prevent tool damage or crash during ATC sequences.

Causes and Fixes

1
Check NC program for M05 (spindle stop) command before M06. Ensure M05 is programmed at least one block before tool change command. Review program lines preceding alarm occurrence.
2
Navigate to POSITION > ACTUAL (SPINDLE) screen and verify spindle speed displays 0 RPM. If spindle shows residual rotation after M05, increase dwell time using G04 P2000 (2 second dwell) between M05 and M06.
3
Check Parameter 3741.0 (Spindle Zero Speed Detection Width). Typical value is 10-50 RPM. If set too narrow, spindle may not register as stopped. Adjust via SYSTEM > PARAM > 3741 if necessary.
Changing spindle parameters may affect orientation and rigid tapping. Document original values before modification.
4
Verify spindle orientation complete signal (DI signal for spindle orient completion, typically SPOS or ORCMA) is active. Check PMC ladder diagram and I/O signals via DIAGNOSIS > PMC > DGN > I/O. Confirm orient complete coil is ON before M06.

DIY Feasiblehigh confidence

Call a technician if:

·Encoder replacement needed
·PMC ladder modification required
·Spindle motor issues suspected

Prevention

Regular spindle encoder maintenance
Proper M05/M06 programming sequence
Monitor spindle deceleration times during setup

Common Mistakes

Setting stop detection time too short
Ignoring encoder signal quality
Not allowing sufficient dwell time after M05

Related Alarms

348 350 401 402

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