This is the most serious consequence. You calculated the shift in the wrong direction. Always test with a dry run and the rapid override turned to 25% or lower.
Parameter 1860 (Movement Pulse) is a critical servo initialization parameter. It defines the distance the machine axis moves for every single pulse of feedback emitted by the encoder or scale. Essentially, it establishes the mathematical relationship between the electrical pulses detected by the CNC and the physical mechanical travel of the axis.
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.
Fanuc Parameter 1860 is not a "set and forget" value. It is a dynamic tuning lever that balances the competing demands of speed (cycle time), accuracy (corner fidelity), and stability (vibration-free cutting).
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.
Final Pro Tip: Regularly review Parameter 1860 as part of your preventive maintenance schedule. After six months of heavy use, ballscrew wear can change the system's inertia, and a once-perfect 1860 value may need a 10-20% increase to maintain smooth motion.
References: Fanuc 0i-D, 0i-F, 31i-B5 Series Connection Manual (B-64643EN) and Parameter Manual (B-64640EN). Always consult your specific machine tool builder's documentation as they may override standard Fanuc recommendations with custom PMC logic or secondary parameters.
On a Fanuc CNC system, Parameter 1860 (also known as GRIDX) is a critical axis-specific setting used to define the grid shift amount for the reference position (home position).
This parameter is typically used during machine setup or maintenance to fine-tune the machine���s zero point without physically moving the limit switches or reference cams. Quick Breakdown of Parameter 1860 fanuc parameter 1860 full
Function: Adjusts the electrical reference position by a specific number of pulses (detection units). Data Type: 2-word (Signed long integer).
Unit: Detection units (the smallest increment the machine can move).
Applicability: Essential for systems using incremental or absolute pulse coders where the "Grid Method" is used for zero return. Why Adjust Parameter 1860?
You would change this value if your machine���s home position is physically "off" by a small, consistent amount. Instead of re-mounting a cam or switch, you enter a "shift" value here to tell the control where the true zero is relative to the first grid pulse it detects. How to Set It
Enable PWE: Put the machine in MDI Mode. Go to the SETTING page and set PARAMETER WRITE (PWE) to 1. (Note: This will trigger a P/S 100 alarm, which is normal).
Find the Parameter: Press the SYSTEM hard key, then the PARAM soft key. Type 1860 and press NO. SRH.
Enter the Value: Select the axis you want to adjust (X, Y, Z, etc.) and input the new value.
Positive values shift the reference position in the positive direction. Negative values shift it in the negative direction. This is the most serious consequence
Restart: For the changes to take effect, you must cycle the power of the machine.
Disable PWE: After rebooting, set PARAMETER WRITE back to 0 and press RESET to clear the alarm. Pro-Tip: The Grid Shift Limit
Be careful not to set a value larger than the grid reference distance (the distance between two encoder "grid" pulses). If the shift is too large, the machine might skip a grid and home to the wrong position entirely.
Need help calculating the exact shift value for your specific axis? How to Enable Parameter Write Enable (PWE) on a Fanuc CNC
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.). Fanuc Parameter 1860 is not a "set and forget" value
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
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
Here haven't found any official source stating that Fanuc Parameter 1860 is "Full" or related to memory capacity. Fanuc Parameter 1860 is typically related to Acceleration/Deceleration (Interpolation).
Here is the interesting "hidden" feature regarding this parameter that many machinists overlook: