| Machine Type | Typical 1860 Value (mm/min) | Reason | |--------------|-----------------------------|--------| | Small milling | 500 – 2000 | Short deceleration zone, slower dog approach | | Large lathe | 2000 – 6000 | Heavy axis, needs consistent dog capture | | High-speed machining center | 1000 – 4000 | Balanced speed vs. repeatability | | Grinder | 200 – 1000 | Very fine reference accuracy required |
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
✅ The second stage uses a slower speed to ensure the reference point is captured cleanly by the deceleration dog & position coder 1‑revolution signal — preventing overshoot or false reference return.
Fanuc (often referred to as P1860 ) is a critical setting used to define the Position Deviation Limit (Position Error) during a stop or at rest . It essentially sets the "allowable window" for how far an axis can drift from its commanded position before the CNC triggers a Servo Alarm (typically SV0410) . 1. Purpose of Parameter 1860 fanuc parameter 1860 full
: It is typically a 2-word (long integer) axis-specific parameter.
: Detection unit (e.g., 0.001mm or 0.0001 inch depending on machine settings). Technical Role
It is critical to understand that Parameter 1860 is not a "global constant" across every single FANUC firmware version. Depending on your specific model and the options installed, the function of 1860 shifts slightly. | Machine Type | Typical 1860 Value (mm/min)
By fine-tuning parameter 1860, users can optimize the advanced preview function to suit specific machining requirements, such as:
While overlooked by many, Parameter 1860 is key to the machine's "memory" of where it is in space. This guide explains what this parameter does, its different functions in various FANUC systems, and the correct procedures for setting it up to ensure your machine establishes its reference points quickly and consistently.
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. The physical distance between where the machine should
One of the most practical uses of Parameter 1860 occurs during procedures. This is often required after:
Incorrectly modifying Parameter 1860 can cause the machine to "lose" its position, potentially leading to crashes if the software limits no longer align with the physical machine limits. Are you currently dealing with a specific alarm code (like 300 or 309) after a battery change? How to Enable Parameter Write Enable (PWE) on a Fanuc CNC
How does FANUC set the backlash compensation parameters on t