Fanuc Parameter 1860 Full
A 4th or 5th axis rotary table has high inertia. Setting 1860 too low on the rotary axis will cause "clunking" on start/stop. Fix: For a rotary axis, start with 1860 = 150 ms. Increase until motion is smooth, even if it slows indexing.
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:
| Item | Value / Note | |-------------------|-----------------------------------------------| | Function | 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 |
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.
Fanuc Parameter 1860 (Position of the absolute position detector) is a read-only parameter that displays the current position value from the absolute pulse coder. While it is not a setting you typically edit manually, it serves as a critical reference point for the CNC system to maintain axis alignment without needing to re-home after a power cycle. Key Characteristics and Function Data Type: 4-word (integer). fanuc parameter 1860 full
Function: It tracks the absolute position of each axis. This value is automatically set and updated by the CNC when an axis is zeroed (specifically through Parameter 1815 APZ).
Usage: Maintenance technicians use this parameter to verify that the absolute pulse coder is correctly tracking the machine's physical position.
Modular Arithmetic: The value may "wrap around" based on the encoder's count limits, which is normal behavior for absolute detectors. Related Reference Parameters
When troubleshooting absolute position issues, you will likely need to check these associated parameters:
Parameter 1815: Used to set the absolute position reference (Bit 4: APZ).
Parameter 1850: Sets the grid shift amount to fine-tune the zero position. Parameter 1851: Controls backlash compensation. Safety Note A 4th or 5th axis rotary table has high inertia
Do not attempt to force a value into Parameter 1860. On most systems, it is read-only. To change the machine's reference position, use the proper zero-point setting procedure involving Parameter 1815.
Are you experiencing a specific alarm code or axis shift that led you to check this parameter? FANUC? M6 toolchange position. | Practical Machinist
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. Example Use Case:
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