Parameter 1860 a crucial axis-specific setting used to define the
position of each servo axis on the FSSB (Fanuc Serial Servo Bus) when using manual configuration
. It essentially tells the CNC control which physical amplifier and slave unit corresponds to which logical axis (like X, Y, or Z). How it Works
In modern Fanuc systems (like the 16i, 18i, 21i, and 0i series), the control communicates with servo amplifiers through a high-speed fiber-optic bus called Automatic vs. Manual
: Most machines use "Automatic Setting" (set via Parameter 1902), where the system detects the amplifiers in order. The Role of 1860
: When manual setting is required—often for complex configurations or when adding axes—Parameter 1860 is used to assign a specific Slave Number to each axis.
: The value entered in 1860 for a particular axis typically represents the hardware address or "slave" position on the FSSB string. Why It’s "Interesting" Invisible in Standard Manuals fanuc parameter 1860 work
: Because it is an advanced FSSB configuration parameter, it often does not appear in the standard "Backlash" or "Travel Limit" sections of the Practical Machinist threads or basic parameter manuals. Ghost Axes
: If 1860 is set incorrectly, the machine might "see" an axis that isn't there or fail to communicate with a real one, leading to FSSB-related alarms (like System Alarm 920 or 926). Initialization
: When setting up a machine from scratch, changing 1860 usually requires a power cycle
to take effect because the FSSB must re-initialize its entire communication handshake. Related Parameters : Used to set the servo axis number. : Controls whether the FSSB is in automatic or manual mode. : Frequently mentioned nearby in forums, these handle Backlash Compensation for each axis. Further Exploration Learn how to troubleshoot FSSB alarms by reading the FSSB Configuration Guide
Discover why Parameter 1860 is often omitted from standard manuals in this Practical Machinist discussion
Step-by-step instructions for manual FSSB initialization can be found at Are you trying to add a new axis to your machine, or are you troubleshooting a specific FSSB alarm PARAMETER MANUAL Parameter 1860 a crucial axis-specific setting used to
Parameter 1860 controls the Feed per Revolution (FPR) Override limit.
When your G-code program commands a feed rate based on spindle revolutions (e.g., G99 G01 Z-50.0 F0.2), the operator can adjust this feed rate using the Override knob on the control panel (usually 0%, 10%, ..., 150%, 200%).
Parameter 1860 sets the maximum percentage of override the operator can select. Any override selection higher than this parameter’s value will be ignored or clamped to this maximum.
The value you enter is a direct percentage integer.
Scenario A: You want to LOCK the feed to 100%.
Scenario B: You want to limit the override to a maximum of 120%. Scenario A: You want to LOCK the feed to 100%
Scenario C: No Limit (Allow Full Override).
FANUC Parameter 1860 is a real-time compensation value used primarily in spindle control, specifically for synchronous tapping (rigid tapping) and spindle/C-axis synchronization. It is often labeled in FANUC documentation as:
"Synchronous error compensation amount for spindle orientation"
In simpler terms, Parameter 1860 tells the CNC control how much electrical angle adjustment is needed to perfectly align the spindle’s actual position with the commanded position. This parameter directly influences the accuracy of operations like:
The keyword "FANUC parameter 1860 work" is searched by technicians who have seen mysterious tapping failures, misoriented tools, or inconsistent spindle accuracy. Now you know: this small but powerful parameter provides the crucial link between electrical feedback and mechanical reality.
When you understand how FANUC Parameter 1860 works, you stop guessing and start diagnosing. You replace broken taps less often, reduce spindle downtime, and achieve thread quality that passes the tightest inspections.
Take action today:
If you suspect your 1860 setting is off, follow the calibration steps in this guide. Your machine—and your tool budget—will thank you.
