When an axis is successfully homed (set with Parameter 1815.4 APZ), the current encoder count is saved into Parameter 1860.
It typically uses modular arithmetic, meaning the value "wraps around" based on the encoder's pulses per revolution.
It is a critical, read-only system parameter used by the CNC to track exactly where an axis is relative to its reference (home) position. If the value in Parameter 1860 is lost or incorrect—often due to a battery failure—the machine will lose its "sense" of where it is, leading to homing alarms. What is the Function of Parameter 1860? fanuc parameter 1860 work
If the system detects a discrepancy between the physical position and the value in 1860, it may trigger a "Request for Reference Position Return". How Parameter 1860 Works During Startup
If they match within a certain tolerance, the machine "remembers" its position immediately without requiring a manual zero return. Troubleshooting Common 1860 Issues When an axis is successfully homed (set with Parameter 1815
Because Parameter 1860 is a system-generated value, you do not "type in" a value manually. Instead, you perform a procedure to let the CNC update it:
It compares this value against the stored data in Parameter 1860 . If the value in Parameter 1860 is lost
Understanding Fanuc Parameter 1860: Reference Position and Absolute Encoders