Fanuc - Parameter 1860 Full

Advanced programs can modify 1860 on the fly. This is powerful for optimizing roughing vs. finishing in one setup.

Format (Fanuc Macro B):

G10 L50 N1860 P1 R60  (Sets parameter 1860 for axis 1 (X) to 60 ms)
G10 L50 N1861 P2 R80  (Sets parameter 1861 for axis 2 (Y) to 80 ms)
...
G11                   (End parameter input mode)

Example Use Case:

| Parameter | Function | |-----------|----------| | 1850 | Grid shift amount (reference position fine offset) | | 1851 | Reference position coarse shift | | 1820 | Number of pulses per motor rotation / detection unit | | 1420 | Rapid traverse speed | | 1421 | FL speed (deceleration speed for ZRN) | | 3003 (bit 5) | ZRN direction selection |

FANUC Parameter 1860 controls the reference counter size for semi-closed loop axes. A "full" or correct setting ensures one motor revolution corresponds exactly to the counter’s maximum count, providing stable and repeatable reference point return. For most systems, this value is 1 when Parameter 1820 equals the encoder’s reference pulses per revolution. Incorrect values lead to positioning faults and reference point instability. Always verify with machine tool builder documentation before modification.

Disclaimer: Parameter numbers and behavior can vary slightly between FANUC control series (e.g., 0i-TD vs 31i-A). Always refer to the specific FANUC operator’s manual for your control model.

Understanding Fanuc Parameter 1860: Absolute Position Detection

Fanuc Parameter 1860 (often referred to as APZ) is a critical configuration setting in Fanuc CNC systems (such as the Series 0i, 16i, 18i, and 31i) that indicates whether the reference position for an absolute pulse coder has been established for a specific axis.

When a machine is equipped with absolute encoders, it does not require a manual "home" or zero-return operation every time it is powered on, provided the absolute position is correctly saved. Parameter 1860 is the system's "flag" that tells it whether this position is currently valid. 1. The Core Meaning of Parameter 1860

Parameter 1860 is a bit-type parameter where each bit typically corresponds to a different controlled axis (X, Y, Z, etc.).

0: The reference position is not established. The machine does not know its absolute zero, and you will likely see a "Need ZRN" (Zero Return) alarm or a 300-series absolute pulse coder alarm.

1: The reference position is established. The system knows exactly where the axis is located based on the absolute encoder data. 2. When Does Parameter 1860 Revert to 0?

In a perfectly functioning machine, this parameter stays at "1" indefinitely. However, certain events will force it to "0," requiring a re-homing procedure:

Battery Failure: Absolute encoders rely on a backup battery to "remember" their position when the power is off. If the battery dies, the position is lost.

Encoder Disconnection: Unplugging the encoder cable or replacing the motor/encoder resets the stored position.

Mechanical Overhaul: If you disconnect the motor from the ball screw, the physical relationship between the encoder and the machine zero changes.

Manual Reset: A technician may manually change this bit to "0" to force a new home position calibration. 3. How to Set or Reset Parameter 1860 fanuc parameter 1860 full

If you encounter an absolute pulse coder alarm (like Alarm 300), you must re-establish the reference position. Simply typing "1" into Parameter 1860 is usually not enough; the CNC must "see" the machine reach its physical home first. Step-by-Step Recovery Procedure: How to Enable Parameter Write Enable (PWE) on a Fanuc CNC

Fanuc Parameter 1860 is primarily used to set the backlash acceleration amount in specific control series like the Fanuc 15i. In other common series (such as 16i, 18i, and 21i), this function is often mapped to parameter 2048 instead. Key Details for Parameter 1860 (Backlash Acceleration)

Function: 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:

1861 (15i) / 2071 (16i/18i/21i): Defines the time period (usually in 2ms units) that the backlash acceleration remains effective.

2003 bit 5 (16i/18i/21i): Known as BLEN, this bit must be set to 1 to enable backlash acceleration functions. Commonly Confused Parameter: 1815

Users searching for "1860" in the context of absolute encoders or home positions are often actually looking for Parameter 1815, which is critical for resetting axis reference positions.

1815 Bit 4 (APZ): Indicates if the reference position (zero point) is established. If it is 0, a 300 APC alarm occurs.

1815 Bit 5 (APC): Specifies whether an absolute pulse coder is used for that axis. How to Change Parameters

To modify these or any other system parameters, follow these steps: How to Enable Parameter Write Enable (PWE) on a Fanuc CNC

In Fanuc CNC systems (Series 16i/18i/21i and 0i-MODEL B/C/D/F), Parameter 1860 current position of the Absolute Pulse Coder (APC) at the reference position. While parameter is used to tell the control "where" home is, parameter

is the underlying numerical value the encoder reports at that exact spot. It is almost never manually edited by an operator; instead, the CNC system calculates and updates this value automatically when you perform a reference point return or set the (Absolute Position Zero) bit. ⚙️ The Mechanics of Parameter 1860

: Stores the APC counter value when the axis is at the reference point. Relationship to 1861 : Because APC values can be very large, parameter

is often used as a continuation of 1860 to handle higher-order bits. : Typically a 2-word axis

type, meaning it can store large integers separately for each axis. ⚠️ When to Interact with 1860 Reference Point Recovery

: When an absolute encoder battery dies, the machine "forgets" the relationship between its physical position and the encoder count. Setting 1815 bit 4 (APZ)

to 1 at the correct physical location triggers the CNC to take the current encoder reading and write it into Maintenance Warnings : Changing manually will force a Power Cycle (Alarm 000) and will likely cause the to reset to 0, requiring a new homing procedure. 🛠️ How to View and Set Reference Positions Advanced programs can modify 1860 on the fly

If you are looking for "1860 full" because you are resetting your machine's home after a battery failure, follow this standard procedure: Series 16i-18i -MODEL B - Parameter Manual.pdf - Drivesul

Understanding FANUC Parameter 1860: A Comprehensive Guide

FANUC, a renowned Japanese company, is a leading manufacturer of industrial robots, CNC machines, and other automation solutions. In the realm of CNC machining, FANUC's control systems are widely used for their precision, reliability, and flexibility. One crucial aspect of FANUC's control systems is the parameter setting, which allows users to customize and optimize the machine's performance. In this article, we will delve into the specifics of FANUC parameter 1860, exploring its significance, functions, and configuration.

What is FANUC Parameter 1860?

FANUC parameter 1860 is a specific setting within the FANUC control system that relates to the machine's operation and performance. This parameter is part of a larger system of parameters that allow users to customize and fine-tune the CNC machine's behavior. Parameter 1860, in particular, is associated with the "High-speed machining" or "Advanced preview" function.

Function of FANUC Parameter 1860

The primary function of parameter 1860 is to control the advanced preview function, which enables the CNC machine to predict and optimize the machining process. This feature allows the machine to:

By fine-tuning parameter 1860, users can optimize the advanced preview function to suit specific machining requirements, such as:

Configuration of FANUC Parameter 1860

The configuration of parameter 1860 involves setting a specific value that determines the level of advanced preview and optimization. The value range for this parameter varies depending on the FANUC control system version and the specific machine model.

Typically, parameter 1860 is set to a value between 0 and 100, where:

When setting parameter 1860, users should consider factors such as:

Best Practices for Setting FANUC Parameter 1860

To maximize the benefits of parameter 1860, follow these best practices:

Common Issues and Troubleshooting

If issues arise after setting parameter 1860, consider the following: Example Use Case:

By understanding and effectively utilizing FANUC parameter 1860, CNC machine users can unlock the full potential of their machines, achieving improved machining performance, reduced cycle times, and enhanced productivity.

WARNING: Changing servo parameters can cause axis runaways or crashes. Clear the machine work zone and be prepared to hit E-STOP immediately.

| 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 you execute G28 X... Y... Z..., the reference point return occurs in two distinct phases:

| Phase | Action | Speed Control | Parameter | |-------|--------|---------------|-----------| | 1 | Move from current position to an intermediate point (specified in G28 block) | G00 rapid rate | Parameter 1420 (Rapid traverse) | | 2 | Move from intermediate point to the machine reference point | Lower speed for final approach & deceleration | Parameter 1860 |

✅ Why separate speed?
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 Parameter 1860 is a critical axis-specific setting used to store and manage the absolute position data for machines equipped with absolute pulse coders. It works in tandem with Parameter 1815 to ensure the CNC control "remembers" its exact physical location, even after power cycles, eliminating the need for manual zero-return (homing) operations every morning. Core Function and Purpose

The primary role of Parameter 1860 is to hold the coordinate value that aligns the machine's physical position with the feedback from the absolute encoder.

Absolute Position Storage: It records the current position of each axis relative to the reference point.

Reference Maintenance: When the machine is powered off, the absolute encoder (supported by a battery) keeps track of movement. Upon power-up, the control compares this data with Parameter 1860 to restore the absolute coordinate system immediately.

Rotation Handling: For rotary axes, Parameter 1860 is used to manage the 0-degree or rounding values (e.g., 360 degrees) to ensure the position updates correctly as the axis rotates. The Relationship Between Parameter 1860 and 1815

You cannot effectively manage Parameter 1860 without understanding Parameter 1815, as they are the two halves of the absolute positioning system.

Parameter 1815.4 (APZ): This bit indicates if the reference position for an axis has been established (1 = established, 0 = not established).

Parameter 1815.5 (APC): This bit determines if an absolute position detector is being used for that axis (1 = absolute, 0 = incremental).

Automatic Updating: In standard procedures, manually performing a reference return after setting 1815.4 to '0' will cause the CNC to automatically update the value in Parameter 1860 and then flip 1815.4 back to '1'. How to Set or Reset Parameter 1860

If you encounter a "300 APC Alarm: Need ZRN" (Zero Return Needed), typically caused by a dead battery, you must re-establish the relationship between the physical machine and the encoder data. How to Enable Parameter Write Enable (PWE) on a Fanuc CNC

Fanuc Parameter 1860 stores the absolute encoder pulse count for each axis, which is crucial for resolving 300 APC alarms caused by lost positional data, often due to dead batteries. Fixing the alarm involves replacing the batteries, setting Parameter 1815 (bit 4) to 1, and re-establishing the physical home position to automatically update Parameter 1860. For detailed instructions, you can read the Practical Machinist discussion and CNCmakers technical support. CNC Fanuc Resetting home position After switching batteries