Fanuc Parameter 1860 Full !!link!! -

Fanuc Parameter 1860 is a critical axis-specific setting used to store and manage the absolute position data for machines equipped with absolute pulse coders. It works in tandem with Parameter 1815 to ensure the CNC control "remembers" its exact physical location, even after power cycles, eliminating the need for manual zero-return (homing) operations every morning. Core Function and Purpose

The primary role of Parameter 1860 is to hold the coordinate value that aligns the machine's physical position with the feedback from the absolute encoder.

Absolute Position Storage: It records the current position of each axis relative to the reference point.

Reference Maintenance: When the machine is powered off, the absolute encoder (supported by a battery) keeps track of movement. Upon power-up, the control compares this data with Parameter 1860 to restore the absolute coordinate system immediately. fanuc parameter 1860 full

Rotation Handling: For rotary axes, Parameter 1860 is used to manage the 0-degree or rounding values (e.g., 360 degrees) to ensure the position updates correctly as the axis rotates. The Relationship Between Parameter 1860 and 1815

You cannot effectively manage Parameter 1860 without understanding Parameter 1815, as they are the two halves of the absolute positioning system.

Parameter 1815.4 (APZ): This bit indicates if the reference position for an axis has been established (1 = established, 0 = not established). Fanuc Parameter 1860 is a critical axis-specific setting

Parameter 1815.5 (APC): This bit determines if an absolute position detector is being used for that axis (1 = absolute, 0 = incremental).

Automatic Updating: In standard procedures, manually performing a reference return after setting 1815.4 to '0' will cause the CNC to automatically update the value in Parameter 1860 and then flip 1815.4 back to '1'. How to Set or Reset Parameter 1860

If you encounter a "300 APC Alarm: Need ZRN" (Zero Return Needed), typically caused by a dead battery, you must re-establish the relationship between the physical machine and the encoder data. How to Enable Parameter Write Enable (PWE) on a Fanuc CNC Step 4: Disable and Test

Step 4: Disable and Test

  • Return to the SETTING screen and set PWE back to 0.
  • Press RESET to clear the alarm.
  • Always test with a safe air cut or low feedrate override (10%) before running production parts.

A. Preventing Inconsistent Home Position

If the machine loses reference position after power-off or experiences gradual home position drift, increasing P1860 slightly (e.g. from 500 to 2000) gives the control more tolerance to find the nearest grid point. However, this should not be used to mask mechanical issues (worn dogs, dirty limit switches, loose couplings).

Die and Mold Finishing

For finishing passes with very small feedrates (F 500–2000 mm/min) and fine stepovers, a lower 1860 (30–50 ms) is desirable to maintain sharp detail. However, you must ensure the servo gain (1825) is also high (100–200). This combination is called high-gain, fast-response tuning.

Alarm PS 224 (Illegal parameter)

This appears if you enter a value outside the allowable range for your axis configuration. Check your machine's specific Fanuc manual.