| Parameter | Axis | Function | | :--- | :--- | :--- | | | X | Absolute reference position (low word) | | 509 | Z | Absolute reference position (high word combined with 508) |

Many operators fear these parameters because changing one can cause a crash. However, with a clear strategy, adjusting them is not only safe but necessary for machine reliability, accurate tool changes, and eliminating annoying alarms.

will use these values to automatically set the Work Coordinate System upon a manual reference return. X-axis value. Z-axis value. Parameters 700–706 (Travel Limits):

These define the coordinate values for the 2nd reference point (G30 P2).

On a legacy FANUC 0-T, mechanical wear creates "lost motion" between the motor and the table.

Ensure the physical cam (deceleration dog) is clean. The 0T looks for the deceleration signal first, then the next encoder grid mark.