Fanuc Parameter 1860 Full ((link))

In the vast ecosystem of FANUC CNC parameters, certain numbers are famous for simple functions like handwheel feed rates (No. 1430), while others are infamous for their mystery. Parameter 1860 belongs firmly in the second category. Search any FANUC forum, and you will find a trail of confused engineers wondering why their machine lost zero, what the difference is between 1860 and 1861, or why a "Backlash Acceleration" setting is suddenly breaking their rotary axis alignment.

During heavy roughing with large cutter engagement, use a . This provides a "soft start" that prevents the tool from digging in or chipping at corner entries. Some advanced operators even program a macro to change 1860 dynamically via a G10 command based on tool type.

| Item | Value / Note | |-------------------|-----------------------------------------------| | | Grid check window after deceleration dog OFF | | Control series | FANUC 0i-B/C/D, 16i, 18i, 21i, 30i/31i (legacy mode) | | Unit | Detection units (1 µm or 0.1 µm typical) | | Typical value | 1000 – 5000 | | Alarm if exceeded | PS0090, SV0413 | | Effect of increase | More tolerance, less alarms; risk of wrong grid | | Effect of decrease | Stricter check; may cause false alarms | fanuc parameter 1860 full

A "full" or correct setting ensures the reference counter exactly matches the number of position feedback pulses in one motor revolution.

Note: Always refer to your specific FANUC maintenance manual (B-63944EN, B-63525EN, etc.) as parameter mapping and bit assignments can vary between series and firmware versions. In the vast ecosystem of FANUC CNC parameters,

There is no universal "perfect" number for 1860. It depends on your machine's mechanical design, motor torque, and the workpiece material. However, you can calculate a safe starting point.

Where:

Detection Units (Typically 0.001 mm or 0.0001 inch depending on basic increment settings) -99999999 to +99999999 How Parameter 1860 Interacts with the Absolute Encoders

If 1850 = 0, bell-shaped ACC/DEC is effectively disabled, and 1860 behaves as a standard linear time constant. Search any FANUC forum, and you will find

If this acceleration is too low, the axis won't recover fast enough, leaving a protrusion. If it is too high, the axis will overcompensate, causing a gouge in the opposite direction. 3. Parameter 1860 Typical Settings