FANUC codes
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FANUC Controller

Program/G-code · Intermediate · 5-30 minutes

Alarm 178

Fanuc 178 - Stored stroke limit data error

Alarm 178 indicates corrupted or invalid stored stroke limit data in the CNC system parameters. This typically occurs after battery failure, improper parameter backup/restore, or memory corruption affecting the stroke limit check settings stored in non-volatile memory. The control cannot validate or execute the stored limit positions.

FANUCProgram/G-codeIntermediate5-30 minutes

178

Fanuc 178 - Stored stroke limit data error

STORED STROKE LIMIT DATA ERROR

Fanuc PS program alarm 178: STORED STROKE LIMIT DATA ERROR. This alarm is triggered by an illegal or incorrectly formatted command in the part program, or a programming condition that the Fanuc control cannot execute.

Root Cause Summary

Alarm 178 indicates corrupted or invalid stored stroke limit data in the CNC system parameters. This typically occurs after battery failure, improper parameter backup/restore, or memory corruption affecting the stroke limit check settings stored in non-volatile memory. The control cannot validate or execute the stored limit positions.

Safety

  • Verify corrected program or parameters before resuming machining

Causes and Fixes

  1. 1

    Check battery voltage on the CPU board. Should read 3.0-3.6VDC for lithium batteries. Replace if below 3.0V.

    Power off the machine and wait 10 minutes before replacing battery to allow capacitors to maintain memory during swap.

  2. 2

    After battery replacement, load a known good parameter backup file using FLADDER or memory card.

    Ensure backup file matches exact control model and software version to avoid further parameter corruption.

  3. 3

    Verify stored stroke limits in parameters 1320-1327 (varies by control series). Check that values are logical and within machine physical limits.

  4. 4

    Perform a parameter write enable (PWE), set bit 0 of parameter 8900 to 1, then cycle power to initialize stored stroke limit data.

    Document all parameter changes before modification. Incorrect PWE operations can disable the machine.

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