What causes FANUC alarm 092?

Workpiece coordinate offset or tool offset error placing the commanded position away from the reference point. Machine position drift due to a skipped step or servo fault earlier in the program. G27 commanded after coordinate system rotation or scaling that was not cancelled. Reference point position parameter incorrect or changed. Mechanical backlash or servo settling issue causing the axis to stop outside the tolerance zone.

How do I fix FANUC alarm 092?

1. Check the active coordinate system (G54-G59) and work offsets — incorrect offsets will place the axis away from home. 2. Verify no scaling (G51) or rotation (G68) is active when G27 is executed. 3. Check the reference point check tolerance parameter and compare to actual position error. 4. Run G28 to perform a full reference return and then retry G27. 5. Check for any servo alarms earlier in the program cycle that may have caused position loss.

axismd.ai

FANUC Controller

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

Alarm 092

Fanuc Alarm 092 - ZERO RETURN CHECK (G27) ERROR

Fanuc Alarm 092 occurs when a G27 (Reference Position Return Check) command is executed and the CNC determines the specified axis is not at the zero reference position within the tolerance defined in parameter No. 1826. This typically indicates mechanical positioning error, reference position parameters incorrectly set, or grid shift between current position and stored reference position.

FANUCProgram/G-codeBasic15-30 minutes

092

Fanuc Alarm 092 - ZERO RETURN CHECK (G27) ERROR

ZERO RETURN CHECK (G27) ERROR

Root Cause Summary

Fanuc Alarm 092 occurs when a G27 (Reference Position Return Check) command is executed and the CNC determines the specified axis is not at the zero reference position within the tolerance defined in parameter No. 1826. This typically indicates mechanical positioning error, reference position parameters incorrectly set, or grid shift between current position and stored reference position.

Safety

Ensure clear axis travel path before homing to prevent collisions
Ensure the machine is in a safe state before attempting to home the axes. Be aware of potential pinch points and moving parts.
Be prepared to stop the machine immediately if any unexpected or erratic movement occurs during the homing sequence.
If troubleshooting involves electrical components, disconnect power to the machine and follow proper lockout/tagout procedures.
Consult the machine's safety manual for specific safety precautions related to homing and axis movement.
Ensure no personnel are near moving parts during operation.
Wear appropriate personal protective equipment (PPE).
Power down the machine if an obstruction is suspected to prevent injury.

Causes and Fixes

1
Navigate to POSITION screen and verify current Machine Coordinate (absolute position) for the alarm axis matches the expected reference position value stored in parameters No. 1250-1253 (reference position for each axis).
2
Check parameter No. 1826 (G27 check tolerance) - typical value is 100 to 500 (0.01mm to 0.05mm in metric). If set too tight, increase slightly to 200-300 and retest G27 command.
3
Execute manual reference position return (G28) for the affected axis, then navigate to DIAGNOSIS screen No. 300 (ZRN - Zero Return Complete bit) and verify bit for the axis shows '1' indicating successful reference position establishment.
4
Re-execute G27 command. If alarm persists, check DIAGNOSIS screen No. 308 (In-Position check) for the axis - if not stable at '1' when stationary, investigate servo gain parameters (No. 1825, 1826) or mechanical binding.
Do not modify reference position parameters No. 1250-1253 unless you have verified grid shift or performed machine re-leveling

DIY Feasiblehigh confidence

Call a technician if:

·Repeated reference position loss
·Encoder feedback errors
·Mechanical binding during reference return

Prevention

Regular battery replacement
Verify reference return after power cycles
Include G28 reference return in program startup

Common Mistakes

Assuming reference is maintained after power loss
Ignoring small position deviations
Not verifying reference position after maintenance

Related Alarms

401 402 410 411

Seeing Multiple Alarms?

Seeing another alarm with this one? Enter the code.

Get machine-aware diagnosis

AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.

Start free

Was this guide helpful?

Always verify with your machine manual or a certified technician before performing service procedures.