Haas codes
HaasOvertravel/LimitBasic10-20 minutes

146

Haas 146 - Y LIMIT SWITCH | Haas CNC Alarm

Y LIMIT SWITCH

This alarm indicates the Y-axis has traveled beyond its software or hardware travel limit and triggered a limit switch input on the MOCON board. The machine will halt all motion immediately and require operator intervention to clear. The MOCON monitors limit switch inputs continuously and this fault prevents damage to the machine by stopping motion before mechanical collision with hard stops or ballscrew ends.

Root Cause Summary

Haas Alarm 146 (-Z Limit) occurs when the Z-axis travels beyond its negative software limit defined in Parameter 221 or activates the physical -Z limit switch. This protective alarm prevents spindle collision with the table, workpiece, or fixture by immediately halting all axis motion when the programmed or physical travel boundary is exceeded.

Safety

  • Tool may have crashed

Causes and Fixes

  1. 1

    Check Tool Offset Values

    Press OFFSET, select TOOL tab, verify H-offset values are positive and reasonable for your tooling setup.

    Tool length offsets should typically range from 0.1 to 6 inches depending on your tool holder system

  2. 2

    Verify G43 Programming

    Review program for proper G43 H__ usage and ensure the H-number corresponds to correct tool offset register.

    Never use negative values in tool length offset registers

  3. 3

    Test with Manual Tool Change

    In MDI mode, command G43 H01 Z1.0 with a known good offset to verify proper Z-axis positioning.

  4. 4

    Reset and Re-measure Tools

    Use TOOL SETTING page to re-measure tool lengths if offsets appear corrupted or incorrect.

DIY Feasiblehigh confidence

Call a technician if:

  • ·Physical limit switch damage or misalignment
  • ·Parameter corruption requiring factory reset
  • ·Mechanical binding in Z-axis movement

Prevention

  • Always verify tool length offsets before running new programs
  • Use graphics simulation to check tool paths
  • Establish consistent work offset procedures
  • Regular verification of Parameter 221 settings

Common Mistakes

  • Entering negative tool length offsets
  • Forgetting G43 activation in programs
  • Incorrect work offset zero point setup
  • Modifying Parameter 221 without understanding machine limits

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