What causes FANUC alarm 190?

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 190?

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 190 specific remedy. 5. Contact Fanuc service if the alarm persists after basic troubleshooting.

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FANUC Controller

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

Alarm 190

Fanuc Alarm 190 - ILLEGAL AXIS SELECTED (G96)

Alarm 190 occurs when constant surface speed mode (G96) is commanded with an invalid axis specified in the P address, or when parameter 3770 contains an illegal axis designation. This alarm indicates the system cannot identify which rotational axis to use for surface speed calculation.

FANUCProgram/G-codeIntermediate15-30 minutes

190

Fanuc Alarm 190 - ILLEGAL AXIS SELECTED (G96)

SYSTEM ALARM 190

Root Cause Summary

Alarm 190 occurs when constant surface speed mode (G96) is commanded with an invalid axis specified in the P address, or when parameter 3770 contains an illegal axis designation. This alarm indicates the system cannot identify which rotational axis to use for surface speed calculation.

Causes and Fixes

1
Review the G96 block in the NC program. Check format: G96 S[surface_speed] P[axis_number]. The P value must correspond to a valid rotational axis (typically C-axis = 3rd axis).
2
Navigate to SYSTEM > PARAM and verify parameter 1022 (axis name assignment). Confirm the axis specified in P address matches a configured rotational axis in the system.
3
Check parameter 1006 bit 4 (C-axis enable) and parameter 5440-5443 (C-axis configuration). Ensure the rotational axis referenced by P is properly enabled for surface speed control.
4
Correct the G96 P value to match the actual rotational axis number. For standard lathe with C-axis, use G96 S[speed] P3 or omit P if only one spindle exists.

DIY Feasiblehigh confidence

Call a technician if:

·Parameter 3770 changes don't resolve alarm
·Servo configuration issues suspected
·System type reconfiguration needed

Prevention

Always verify axis numbers before using G96 P address
Document parameter 3770 setting in machine setup sheets
Use program simulation to catch G96 errors before runtime

Common Mistakes

Using axis numbers that don't exist on the machine
Confusing physical axis letters (X,Z) with parameter axis numbers (1,2,3)
Copying lathe programs to milling machines without modification

Related Alarms

191 010 400

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