What causes FANUC alarm 096?

Operator attempted a P-type program restart after modifying workpiece origin offset values (G54-G59) between the original run and the restart. Work coordinate offset was changed or accidentally edited while the program was interrupted mid-cycle, making P-type restart invalid. Operator used program restart type P (sequence number search restart) without realizing the control detected a mismatch in workpiece offset data from when the program originally ran. MDI offset adjustment was made during a feed hold or emergency stop before attempting to resume with a P-type restart. Macro variable or external offset change altered the work offset values after the program was halted, triggering the control's restart validation check.

How do I fix FANUC alarm 096?

1. Do not use P-type restart in this situation. Instead, use a different restart method such as restarting from the beginning of the program or using a sequence number search that does not require P-type specification. 2. Check your workpiece origin offsets (G54-G59) and compare them to what they were when the program originally started. If they were changed, restore them to the original values before attempting any restart. 3. If the offset change was intentional and necessary, restart the program from the beginning rather than mid-program to ensure the control has consistent offset data throughout the entire run. 4. Clear the alarm by pressing RESET, then verify all work offsets are correct and stable before restarting. Do not modify any offset values after this point until the program completes. 5. If you must restart mid-program after an offset change, manually position the machine to a safe location and use a block search or sequence number restart method that the control will accept under these conditions. 6. Review the program restart procedure in your machine's operation manual to confirm which restart types are permitted after offset changes, and train operators to avoid editing offsets during interrupted cycles.

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FANUC Controller

Program/G-code · Intermediate · 10-20 minutes

Alarm 096

Fanuc Alarm 096 - P TYPE NOT ALLOWED (WRK OFS CHG)

Fanuc Alarm 096 occurs when attempting to restart a program using P-code (program restart with sequence number search) after the workpiece coordinate system offset (G54-G59, etc.) has been changed. The CNC system detects that the work offset values have been modified since the program was interrupted, making P-type restart unsafe as tool position relative to the workpiece is no longer valid.

FANUCProgram/G-codeIntermediate10-20 minutes

096

Fanuc Alarm 096 - P TYPE NOT ALLOWED (WRK OFS CHG)

File Error

Root Cause Summary

Fanuc Alarm 096 occurs when attempting to restart a program using P-code (program restart with sequence number search) after the workpiece coordinate system offset (G54-G59, etc.) has been changed. The CNC system detects that the work offset values have been modified since the program was interrupted, making P-type restart unsafe as tool position relative to the workpiece is no longer valid.

Safety

Backup important files
⚠️ BACKUP CRITICAL FILES before troubleshooting to prevent data loss
Ensure the machine is in a safe state (e.g., emergency stop activated) before performing any maintenance or troubleshooting.
Disconnect power to the CNC controller before performing any internal hardware checks or modifications. Follow proper lockout/tagout procedures.
Be aware of potential mechanical hazards (e.g., moving parts) when working around the CNC machine.
Consult the CNC machine's documentation or a qualified technician if you are unsure about any troubleshooting steps.

Causes and Fixes

1
Press RESET to clear alarm 096. Cancel the P-type restart attempt.
2
Navigate to OFFSET/SETTING screen and verify current work offset values (G54-G59). Compare against setup sheet or documented values to confirm changes were made during program interruption.
3
If work offset change was intentional, restart program from beginning (O-number start) rather than using P-code sequence number restart. If work offset change was accidental, restore correct offset values and restart program from beginning.
Never use P-type restart after changing work offsets. Tool position relative to part will be incorrect and collision/crash will likely occur.
4
If mid-program restart is required, use manual positioning to safe Z-height, reselect correct work offset with G54-G59 command in MDI, then restart program from appropriate sequence number without P-code, or use machine lock and single block to verify tool path.

DIY Feasiblehigh confidence

Call a technician if:

·Parameter access is restricted
·Repeated coordinate system corruption
·External communication system integration issues

Prevention

Set parameter 3202 bit 6 to prevent offset changes during program execution
Use tool offsets instead of workpiece offsets for wear compensation
Implement proper program pause/restart procedures in operator training
Enable offset change logging via parameter 3112 for troubleshooting

Common Mistakes

Adjusting workpiece offsets instead of tool offsets for wear compensation
Assuming P-type restart is always safe after any program interruption
Not checking coordinate system status before restart attempts
Modifying offsets without understanding impact on restart procedures

Related Alarms

010 020 021 097

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