Understanding and correctly setting Parameter 1860 is essential for ensuring that the rotary axis behaves predictably, especially when moving beyond 360° or using absolute encoders. 1. What is Parameter 1860? (Full Definition)
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. fanuc parameter 1860 full
It defines the amount of offset added to the velocity command immediately following a reversal in axis direction to compensate for mechanical backlash. Typical Setting Range: 20 to 600. Related Parameters: (Full Definition) In the vast ecosystem of FANUC
value used to adjust the zero point after a reference return. Maintenance & Troubleshooting Read-Only Nature Search any FANUC forum, and you will find
The best approach is systematic: start with the machine builder's recommendation, use the acceleration formula to find a theoretical minimum, test with a representative part, and adjust in small increments. By mastering Parameter 1860, you unlock the true performance potential of your Fanuc CNC—moving from a machine that just "runs" to one that runs efficiently, accurately, and reliably.
Technicians often confuse 1860 with other parameters. Here is a clear comparison:
An incorrect setting in Parameter 1860 will result in the machine moving an incorrect distance (e.g., commanding 100mm but moving 50mm or 200mm), rendering the machine unable to perform accurate machining or threading.