Comprehensive Parameter Guide for FANUC CNC Controls

30 July 2026

Mentor CNC Editör Ekibi

FANUC controllers are the heart of CNC machines, and correct parameter settings are what let them reach maximum performance. In this guide we cover the most critical parameters, functions, and setup procedures across different FANUC control series in detail.

📌 REFERENCE POINT (HOME) SETTINGS

1815 – APC and APZ (Reference Point Establishment)

Applies to: All CNC lathes and machining centers

This parameter is used to establish the reference point (home position) on machines equipped with an absolute encoder (Absolute Pulse Coder).

How to do it:

1. Power off the machine

2. Using the handwheel, move the X and Z axes to the reference point

3. In parameter 1815, set the APC and APZ bits (bits 4 and 5) to “1”

4. Power the machine off and back on

⚠️ Warning: After a battery replacement the APC and APZ bits can reset. If the reference point is lost, this procedure must be repeated.

1850 – Grid Shift

Applies to: All FANUC controls

Used to fine-tune the reference point. It adds an extra shift to the reference point equal to the value entered. For Grid Shift to be active, parameter 1002#2 must be “1”.

🎯 DECIMAL POINT SETTINGS

3401#0 (DPI) – Decimal Point Suppression

Applies to: 0i-MB controls

Removes the requirement to use a decimal point (.) in FANUC programming.

  • DPI = 1: Values entered without a decimal point are read as mm/1000 (microns)
  • DPI = 0: The standard decimal-point requirement remains in effect

P.15#7 – Cancel Decimal Point in Program

Used to cancel decimal points written during the program.

🔄 4TH AXIS (ROTARY AXIS) SETTINGS

4th Axis Addition Parameters

Applies to: 0i-MB / 0i-MC controls

ParameterValueDescription
99004Number of CNC-controlled axes
81304Total number of controlled axes
10104Number of CNC-controlled axes

Note: The correct Motor ID (2020) must be entered and the machine must be restarted.

4th Axis Cancellation

Applies to: 0i-MC control

  • Bit 7 of 1005 and 1012 = “1” → 4th axis disabled
  • Bit 7 of 1005 and 1012 = “0” → 4th axis enabled

4th Axis 360° Rollover

1006#0 = 1 → After a 360° revolution the 4th axis resets the machine position value.

18i-MB 4th Axis Commissioning

Bits #0 and #3 of 3115 must be “0” (3115=00000000).

🏗️ HIGH-SPEED MACHINING (AICC)

G5.1 Q1 / G5.1 Q0

Applies to: 0i-MC control

A high-precision machining mode that automatically reduces feedrate at corners.

M03 S... (after the spindle reaches speed)
G5.1 Q1  (high-speed mode active)
... machining code ...
G5.1 Q0  (mode off - before M30)

🎛️ SPINDLE SETTINGS

M19 Spindle Orientation Setting

M19 setting parameters across different control series:

ControlParameterDescription
0-MD6577Spindle positioning setting
0i-MB4077M19 position setting
Mitsubishi M703108 or 3107Orientation setting
Mitsubishi M65S3207 (Setup → Spindle)M19 setting

When adjusting with 4077: it works over 4096 pulses. For a 90° change, add or subtract 1024 from the current value.

4030 – Spindle Soft Start/Stop

Applies to: Twinhorn machines

If the spindle knocks during start-up or stopping, set 4030 = 12000.

3735 – Spindle Minimum Speed Setting

Applies to: 0i-MD Twinhorn VP 1500

Minimum clamping speed of the spindle motor.

  • Usually takes a value between 0 and 5
  • Example: 20 is entered and checked as a percentage

🛠️ TOOL CHANGE SETTINGS

Tool Numbering (0-MD Control)

ParameterDescription
D483Tool number in the spindle
D484Tool number in the magazine
D485 – D504From tool 1 to tool 20

Turret Reference Establishment (Lathe)

  • PMM parameter 11#0 = 1 → Establishes the turret reference (first set to “0” and rotate the turret, then set to “1”)

D 401#0 – Turret Position Loss (Goodway TB 150)

This bit becomes “1” when the turret loses position. Setting it to “0” allows the turret to rotate again.

🖥️ DISPLAY AND LANGUAGE SETTINGS

Changing the Language

ControlParameterDescription
18-M3102 (all bits 0)Switches to English
0i-MC (Rifa)3102-3119-3190, all bits 0English menu
Mitsubishi M701043 = 1English

Turning the Graphic Screen On/Off

3112#0 (SGD)

  • = 0: The graphic screen is shown
  • = 1: The Servo Waveform Diagnosis screen is shown instead (the graphic screen does not appear)

3123 – Screen Saver

Parameter 3123 sets the screen-saver timeout in minutes.

8940 – Custom Name on the Startup Screen

To change the name shown on startup, enter a 10-character text string in parameter 8940.

🔧 BALLSCREW BACKLASH SETTINGS

535 – X-Axis Ballscrew Backlash

536 – Z-Axis Ballscrew Backlash

Applies to: 0-T control

Enter the value in microns (µm). It compensates for the play that occurs when the axis reverses direction.

🔌 DATA SERVER CONNECTION SETTINGS

Accuway Data Server (M198 Command)

ParameterValue
30303
205

Twinhorn 0i-MB Data Server

ParameterValue
9990#31
9988#41

⚙️ OTHER IMPORTANT PARAMETERS

5015 – Inner Diameter Adjustment Parameter (0i-TB Lathe)

  • Subtracted if smaller, added if larger

5016 – Outer Diameter Adjustment Parameter (0i-TB Lathe)

  • Subtracted if smaller, added if larger

1466 – Remove Pass Dwell (0i-TC Lathe)

Setting 1466 = 0 removes the dwell while taking a pass.

2496 – Chuck Open/Close Time (0i-TB Lathe)

Changing the timer value shortens the chuck open/close time. Example: 2496 = 496

6710 – Part Counting with M90 (0i-TC Lathe)

Set 6710 = 90. Writing the M90 command above the M99 line enables part counting on Focus machines.

3402#7 – Automatic Mode After M30 (0i-TC Lathe)

When = 1, seeing M30 or pressing Reset makes the machine automatically accept the G96 and G00 codes.

1401#6 – Dry Run Rapid Speed (0i-MC)

When set to = 1, the rapid speed can be controlled in Dry Run mode.

6200#7 – Dry Run

Settings related to the Dry Run function.

518 and 519 – Idle (Rapid) Axis Speeds

Define the rapid axis movement speeds.

60#5 – Motor Load Page

When set to = 1, the motor load page opens.

907#3 – Enable 3rd Axis (Machining Centers)

= 1 enables the 3rd axis.

22#0 and 22#1 – Absolute Encoder References (TA 32)

After the references are set:

  • 22#0 = 1 → X axis accepts the reference
  • 22#1 = 1 → Z axis accepts the reference.

569#0 – System Reset to Start

On vertical machines, if the movement is interrupted mid-way at the tool-change position, set = 1 to return the system to the start.

2113 – Axis Motor Setting

Used for axis motor settings.

5231, 5232, 5233 – Rigid Tapping (M29) Parameters

Gear-ratio settings for rigid tapping:

  • 5231: Position coder tooth count (1st gear)
  • 5232: Position coder tooth count (2nd gear)

5115 – G83/G84/G73 Safety Clearance (0i-MD Twinhorn VP 1500)

Safety clearance setting for peck-drilling cycles. Set a maximum of 2.00.

3104#6 – Tool Length Display (18i-MB)

= 1 → Subtracts the tool length and shows the remaining distance.

3706#6 – Tool Length Display (0i-MC)

Shows the tool length without adding it.

K1.2 – Disable Way Lubrication Pressure Switch (Twinhorn)

= 1 → Disables the way lubrication unit’s pressure switch.

🏭 RIFA MACHINE-SPECIFIC SETTINGS

Dual Pallet Position Settings

Pallet position setting (in programs O9001 and O9002):

ParameterDescription
6954Y -0.1 (98700 is written as 98600 instead)
6932Y +0.1
6931X +0.2
6951X -0.2

Tool Change Position:

ParameterDescription
6950X-axis position value written 100 lower
6931Y-axis position value written 100 lower
6930X-axis position value written 100 higher
6933Z-axis position value written 100 higher

M19 Position Setting (inside the macro):

  • #1132 = 1430 (changed inside O9001)

Sensor Checks:

  • X4.4 = 1 (the window switch separating the two pallets)
  • X5.2 = 0 (sensor indicating the pallet is not clamped)
  • K10.4 = 1 (pallet down)
  • K10.2 = 0 (pallet clamped)

Rifa Horizontal Machining Center

3104#6 and #7 = 1 → The program’s “Z” axis values become the same as the absolute values.

Rifa Tool Change Z-Axis Value (O9001)

  • 6930 = 30100 + 0.1
  • 6950 = 29900 – 0.1

💾 PROGRAM COPYING AND TRANSFER

903#7 – Program Copying (0-MD Control)

Enables the copy function.

0i-MD Running and Transferring from a Card

TAPE → PROGRAM → Right arrow → DIR → OPRT → Right arrow → REFRESH

The card’s contents are displayed.

PLC Loading for Accuway Program Restart

SYSTEM + PMC + I/O + MCARD + READ + EXEC + YES + COMPLETE + ←
22108758 → DISPLAY
G22108758 → EDIT
MCARD + FREAD + EXEC + COMPLETE + RUN + YES

9930#0 = 1 – Program Restart

Enables the program restart function.

📊 FOCUS AND SERVO MOTOR PARAMETERS

Focus Motor Adaptation Parameters

ParameterDescription
2067Motor filter
2012
2021Inertia load

Focus Servo Turret Reset

1. Power off the machine

2. When powering the machine back on, the turret must be in the reference position at tool 1

3. Hold one hand on the hydraulics and one hand on the turret rotation control

4. The counter must read 0

Focus FCL-140

K1#0 = 1 → The part counter stops the machine once the target count is reached.

⚠️ DISCLAIMER

⚠️ MENTOR CNC DISCLAIMER
All technical information, parameter numbers, and procedural steps in this blog post were obtained from machine manuals and technical documentation. However, these details may vary depending on your machine’s brand, model, manufacturer configuration, PLC software, and parameter structure.
For this reason, always record the original values of any parameter before changing it during testing. This lets you revert the change if something goes wrong.
If you have not previously made a Leader PLC, software, or parameter change, be sure to get help from an authorized service provider. Full responsibility for any actions taken rests with the user. Mentor CNC and its content authors cannot be held liable for any malfunction, data loss, or damage that may result.

This guide was prepared for CNC operators and technicians working with FANUC controllers. Always remember to reference your machine’s original documentation as well.

Related Pages

The notes on this page include field observations specific to different FANUC series and certain machine manufacturers. For a more comprehensive, general reference based on your control unit, see: