Fanuc Parameter 1860

: Value 1 for the zero point of the absolute position detector.

The machine will display a flashing "P/S 100 PARAMETER WRITE ENABLE" alarm. This is normal and expected. Step 2: Navigate to Parameter 1860 Press the hard key. Press the PARAM softkey. Type 1860 and press the No. SRCH (Number Search) softkey.

: You must set PWE to 1 on the Setting screen before changes are allowed. Verify Coordinates

The PMC (Programmable Machine Controller) can override reference return speed in some custom cycles. Check ladder rungs referencing address G100 (reference return speed selection). If PMC forces a different speed, Parameter 1860 becomes secondary. fanuc parameter 1860

Yes, this is normal behavior. When you reset APC parameters and re-establish absolute encoder synchronization, new values are automatically calculated and written to parameters 1860 and 1861. These changes should not cause concern as long as the homing procedure completed successfully.

Parameter 1860 specifically applies this logic to or sub-spindle/main-spindle alignments depending on your exact FANUC model and option configuration. It ensures that Axis B (the slave or synchronized axis) mirrors or aligns perfectly with Axis A (the master axis) relative to the machine's physical geometry. Why Adjust Parameter 1860?

Depending on configuration bits, passing the rollover mark can actively trigger an update or hold the reference position values static inside 1860 and 1861 to prevent drift over multi-rotation cycles. When Does Parameter 1860 Change? : Value 1 for the zero point of

| Condition | Symptom | Root Cause | |-----------|---------|-------------| | (e.g., 2000 mm/min on a linear axis) | Axis slams into dog, overshoots reference point, inconsistent home position ± several encoder counts. May trigger overtravel alarm after homing. | High inertia prevents motor from stopping precisely on the marker pulse. | | 1860 too low (e.g., 30 mm/min) | Homing takes excessively long (10-20 seconds per axis). No immediate error, but wasted cycle time. | Creep speed is unnecessarily slow—the marker detection is reliable at moderate speeds. | | 1860 optimal (typical: 100-600 mm/min) | Fast, consistent reference return. Home position repeatable within 1 micron. | Speed allows motor to stop within one encoder count (or fractional count for serial pulse coders). |

If a mechanical slip occurs during a crash, the physical zero-point may no longer match the program zero-point.

The setting values for Parameter 1860 vary depending on the specific FANUC CNC system and the I/O device being used. Here are some common setting values: Step 2: Navigate to Parameter 1860 Press the hard key

| Parameter | Function | |-----------|----------| | | When set to 0, reference point values (parameters 1860, 1861) are changed when machine coordinate crosses 0 degrees. When set to 1, these values are not changed. Used for scales without revolution data | | 1815#5 (APC) | Enables absolute position detector use | | 1815#4 (APZ) | Indicates whether correspondence between machine position and absolute position detector is established |

The specific steps to set parameter 1860 can vary slightly depending on the FANUC CNC system model. Generally, the process involves: