Fanuc Parameter 1860 Full -

Parameter Number: 1860 Parameter Name: Movement pulse (CMR) Data Type: Integer (Valid data range typically 1 to 32767)

Function: This parameter sets the number of pulses required to move the axis by one unit of detection. It is part of the "Calculation of Detection Unit" formula. The CNC uses this value alongside the gear ratio and ball screw pitch to determine the "Detection Unit" (the smallest moveable distance the CNC recognizes).

Some operators shift Z-axis zero (Parameter 1860) slightly positive to gain extra clearance for a large drill or boring bar, though this is dangerous and not recommended for production.

There are three primary reasons a machinist or service technician modifies Parameter 1860:

Parameter 1860 is a critical axis control parameter in FANUC CNC systems (Series 0i, 30i/31i/32i, 15i, 18i, 21i, etc.). It defines the reference counter capacity for an axis operating in semi-closed loop control (using a pulse coder). The term "full" in user queries typically refers to whether the parameter is fully utilized or correctly set to match the machine’s physical configuration—i.e., the full count range required for one revolution of the motor. fanuc parameter 1860 full

Note: Parameter 1860 is used only when:

Before making any change to Parameter 1860, back up all your parameters. One typo can disable the machine.

Method 1 – Punch to computer (RS-232):

Method 2 – Memory Card (if equipped):

Method 3 – Manual documentation: Photograph the parameter screen for 1860, 1850, 1851, and 1815 (APC/APZ settings).

In semi-closed loop systems, the CNC counts feedback pulses from the motor encoder to determine position. When returning to a reference point (grid method), the reference counter counts pulses from a grid signal until it reaches the value set in 1860, then generates the reference point.

In simpler terms:

| Machine Type | Rigidity | Typical 1860 Range (ms) | | :--- | :--- | :--- | | Small VMC (BT30) | High | 30–60 | | Large VMC (BT40/BT50) | Medium | 60–120 | | Heavy-duty lathe (X-axis) | Medium | 80–150 | | Gantry mill (heavy slide) | Low | 120–250 | | High-speed machining center | Very High | 10–40 | Parameter Number: 1860 Parameter Name: Movement pulse (CMR)

When users search for "Fanuc parameter 1860 full," they often need to calculate a value that completely moves zero by a known amount. Here is how to do it correctly.

You need to know your machine's "Least Input Increment" (detection unit).

Example Calculation: Suppose your Z-axis zero is currently 5.000 mm too far toward the spindle (meaning the tool would crash). You need to shift zero positive by 5.000 mm.

Since 1 unit = 0.001 mm: 5.000 mm / 0.001 mm per unit = 5000 units Some operators shift Z-axis zero (Parameter 1860) slightly

Therefore, you would add 5000 to the existing Parameter 1860.