Some control models include Parameter 1860 as a when a two-speed gearbox is present on the axis drive. This is particularly true for older 18MC controls where parameters 1853, 1855, 1856, 1860, 1861, and 1865 are listed in the same axis format but standard manuals skip to 1870. In those legacy systems, 1860 can store one of the gear ratio numerator/denominator pairs.
When a CNC machine executes a rapid traverse command, the CNC command generator calculates where the axis should be at any given millisecond. The servo motor tries to keep up with this command. The physical distance between where the machine should be and where it actually is is called the position deviation. Parameter 1860 dictates exactly how much deviation the system will tolerate at high speeds before triggering an emergency shutdown. The Functional Role of Parameter 1860
Always document the factory-set value before making changes. Use a USB drive, PCMCIA card, or RS-232 connection to take a full SRAM data backup before altering any axis configurations.
It is common to confuse Parameter 1860 with Parameter 1828. While both monitor position deviation, they operate under different conditions: fanuc parameter 1860 full
In practice, for direct drive systems: $$ 1860 = \textReference Counter (1821) \div \textScrew Pitch (in pulses) $$ (Note: This varies heavily depending on whether the machine uses a Decimal Input method or the older Integer Input method.)
Configuration, Function, and Troubleshooting of Parameter 1860 Applicable Systems: FANUC Series 16i, 18i, 21i, 30i, 31i, 32i, 0i-TD/TF, 0i-MD/MF Category: Servo Initialization / Axis Setting
In Fanuc CNC systems, Parameter 1860 is a read-only axis parameter that stores the current position of the absolute position detector (absolute encoder). It is often referred to as the current position in the absolute detector or the "encoder count". Technical Overview Some control models include Parameter 1860 as a
value used to adjust the zero point after a reference return. Maintenance & Troubleshooting Read-Only Nature
Modifying parameter 1860 requires enabling on the control interface. Execute this protocol exactly to avoid software interlocks or crash hazards: Series 16i-18i-MODEL B - Parameter Manual.pdf - Drivesul
If a motor is uncoupled, a ballscrew slips, or a catastrophic crash occurs, the mechanical zero position changes dramatically. The value historically saved in 1860 becomes structurally invalid, throwing position deviation limits or soft overtravel errors. Step-by-Step Guide: Resetting the Reference System When a CNC machine executes a rapid traverse
Never assume Parameter 1860's function based on another machine. Even two machines with the same FANUC controller but different MTBs can use 1860 for completely different purposes.
: The CNC determines whether to dynamically update or preserve the zero-point tracking inside 1860 and 1861. When and Why Does Parameter 1860 Cause Issues?
$$ \textDetection Unit = \frac\textScrew Pitch \times \textGear Ratio\textMotor Revs per Pulse \times 1821 $$