Understanding Fanuc Parameter 1860: Reference Position and Absolute Encoders
Most issues related to Parameter 1860 arise after a or motor replacement.
When an axis is successfully homed (set with Parameter 1815.4 APZ), the current encoder count is saved into Parameter 1860.
If you reset Parameter 1815 but the machine doesn't move to the correct spot, the value in 1860 will often change automatically once a new reference point is established.
These indicate that the absolute position data has been lost.
It typically uses modular arithmetic, meaning the value "wraps around" based on the encoder's pulses per revolution.
If they match within a certain tolerance, the machine "remembers" its position immediately without requiring a manual zero return. Troubleshooting Common 1860 Issues
