Ot Reference Parameter Better: Fanuc

For a Fanuc 0T control, improving or resetting the reference (home) position involves adjusting specific parameters that manage axis movement and grid alignment. Key Reference Point Parameters

To refine or correct the reference position, you typically adjust these settings: Parameter 0700–0703 (Stored Stroke Limits)

: These define the "soft" limits of travel. If you move your reference point, you must often increase these values temporarily (e.g., by 50 mm) to allow the axis to reach the new home position without triggering an overtravel alarm. Parameter 0508–0511 (Grid Shift)

: This is the primary parameter for "fine-tuning" the home position. If your physical home position is slightly off, you enter a value (in microns) here to shift the zero point without moving the physical limit switch. Parameter 0021 & 0022 (Reference Direction/Type)

: These bits control the direction the axis moves to find the reference point and how it handles the deceleration signal. Parameter 1241 (Second Reference Point)

: Sets the coordinate for a secondary home position, often used for tool changes or safe positions in the machine coordinate system. Procedure to Adjust Reference Parameters Enable Parameter Writing (PWE) function key. PWE (Parameter Write Enable)

. An alarm (P/S 100) will appear; this is normal—ignore it while you work. Adjust Stored Stroke Limits

: If you are moving the home position further back, increase the value in Parameter 700 for the relevant axis to avoid early overtravel alarms. Perform the Physical Home

: Manually jog the axis to the desired reference point, usually 1–2 mm before hitting the hard E-stop. Set Grid Shift

: If the position is consistently off by a small amount, use the Grid Shift

parameters (508–511) to offset the internal "zero" from the physical marker pulse. to clear the P/S 100 alarm. Machine Metrics Critical Safety Warning Before modifying any parameters, back up your current settings

to an external PC via the RS-232 interface. Incorrect values can cause the machine to move unpredictably or crash into the hard stops. СервисТЕХ exact grid shift calculation for a specific axis error you're seeing? FANUC Series 30i/31i/32i-MODEL B MAINTENANCE MANUAL

Overview

The FANUC OT reference parameter is a crucial component in FANUC's CNC (Computer Numerical Control) systems, particularly in their OT (Operator's Panel) series. This parameter plays a significant role in setting up and fine-tuning the CNC machine's performance.

Key Features

Precision control: The FANUC OT reference parameter allows for precise control over the CNC machine's movements and operations.
Customization: This parameter can be adjusted to suit specific machining requirements, enabling users to optimize their CNC machine's performance.
Easy setup: The FANUC OT reference parameter is relatively easy to set up and configure, even for users without extensive CNC experience.

Benefits

Improved accuracy: By fine-tuning the reference parameter, users can achieve more accurate machining results.
Enhanced productivity: Optimizing the CNC machine's performance using the FANUC OT reference parameter can lead to increased productivity and reduced cycle times.
Reduced errors: Proper setup and configuration of the reference parameter can minimize errors and reduce the risk of machine crashes.

Comparison to Other Parameters

Compared to other FANUC parameters, the OT reference parameter stands out for its:

Specificity: This parameter is specifically designed for the OT series, providing more precise control over the CNC machine's operations.
Flexibility: The FANUC OT reference parameter can be adjusted to accommodate various machining applications and requirements.

Best Practices

To get the most out of the FANUC OT reference parameter:

Consult the manual: Refer to the FANUC OT series manual for detailed setup and configuration instructions.
Start with default values: Begin with the default reference parameter values and adjust as needed.
Monitor and adjust: Continuously monitor the CNC machine's performance and adjust the reference parameter as required.

Conclusion

In conclusion, the FANUC OT reference parameter is a valuable tool for optimizing CNC machine performance. By understanding its key features, benefits, and best practices, users can unlock improved accuracy, productivity, and efficiency in their machining operations.

To modify any reference parameter on a Fanuc 0T control, you must first enable the system's "Write" mode. : Navigate to the screen and locate PARAMETER WRITE : Change the value from

. The machine will likely trigger a "P/S 100" alarm, which is normal and indicates the system is ready for parameter changes. 2. Option Parameters (The 900 Series)

The 900-series parameters are the "software keys" that unlock specific functionalities within the 0T control. Unlike standard settings, these are often defined bit-by-bit. cncmachinetoolrepair.co.uk Parameter 900

: Controls foundational features like canned cycles (Bit 0) and Inch/Metric conversion (Bit 5). Memory Expansion

: Parameters 901 (Bits 0-4) determine the amount of tape memory available (e.g., 20M to 320M). Custom Macros

: Parameter 902 Bit 6 enables "Custom Macro A," which is vital for complex automated routines. 3. Reference Point & Zero Return Parameters

Establishing the "Home" position is perhaps the most critical task after a battery failure or memory loss. Soft Limits (700-707)

: These parameters define the maximum travel distance in positive (700-703) and negative (704-707) directions from the reference point. Reference Point Shift (708-711)

: These allow for a "shift" between the physical limit switch and the actual machine zero coordinate. G28 Command

: This programmed command sends the axis to the machine's reference position as defined by these parameters. 4. Communication & I/O Channels Fanuc O-T Parameter List Overview | PDF - Scribd

To improve the Fanuc 0-T reference position (homing) feature or adjust the related parameters, you must first enable the ability to edit the system settings and then identify the specific parameter numbers that control axis origin and reference return. 1. Enable Parameter Write (PWE)

Before you can "write" or change any parameter, you must unlock the memory protection:

Mode Selection: Put the machine in MDI mode or Emergency Stop state. Access Setting Screen: Press the [SETTING] function key.

PWE Setting: Find the setting labeled PARAMETER WRITE (PWE) and change it from 0 to 1.

Note: An alarm (usually Alarm 100) will appear indicating PWE is on; this is normal. 2. Key Reference Parameters for Fanuc 0-T

The Fanuc 0-T uses specific parameters to define how it returns to the zero (reference) position: Parameter No. Description 0021 Bit 6 Absolute Pulse Coder

Set to 1 if you want the coordinate system to update without axis motion at power-up. 0708 & 0709 Work Coordinate System fanuc ot reference parameter better

Defines the coordinate values for X and Z when a Manual Reference Return is performed (if Parameter 10.7 is set to 1). 0508 - 0510 Origin Correction Used to fine-tune the X, Y, and Z axis origin points. 1241 2nd Reference Point

Defines the coordinate value of the second reference point in the machine coordinate system. 3. Procedure for Adjusting Reference Position

If you have lost your home position or need to correct it, follow this sequence:

Clear Old Offsets: Temporarily set parameters 508, 509, and 510 to 0. Initial Home: Perform a manual zero return of all axes.

Input New Values: Enter the correct values into parameters 508, 509, and 510 according to your machine's original parameter table. Restart: Turn the power off and then back on.

Final Reference: Perform the manual zero return again to lock in the corrected positions. 4. Important Safety Tips

Backup First: Always back up your current parameters to a PC or USB before making changes.

Incremental Changes: Only change one bit or value at a time and test the movement at a low override speed.

Battery Maintenance: Change the backup battery only while the machine is powered on to avoid losing all parameters. Series 0/00/0-Mate Maintenance Manual, GFZ-61395E/06

Optimizing the reference point on a Fanuc 0T control—specifically the Zero Return (G28) or Home position—is a critical maintenance task that ensures part accuracy and prevents "soft overtravel" alarms. Improving these parameters allows for faster, more repeatable machine homing. 1. The Core Homing Parameters

On the Fanuc 0T, the reference position is typically managed by Grid Shift and Reference Return Direction parameters. Parameter Description 0003 #0–3 ZM

Sets the direction of Reference Position Return for each axis (0: Negative, 1: Positive). 0508 – 0511 Grid Shift

Fine-tunes the physical stop position relative to the encoder's "one-rotation" signal. 0700 – 0707 Soft Limits

Defines the maximum travel limits in machine coordinates. Homing must occur before reaching these values. 1241 2nd Ref Pt

The coordinate for the second reference point (G30), often used for tool change heights. 2. Improving "Grid Shift" for Accuracy

"Better" reference parameters usually mean a more precise Grid Shift. This value compensates for the distance between the deceleration dog (the physical switch) and the encoder's zero mark. Steps to Optimize Grid Shift:

Set to Zero: Temporarily set parameters 508 (X) and 511 (Z) to 0. Home the Axis: Perform a standard Zero Return.

Measure Deviation: Manually move the axis with the MPG (handwheel) to the exact physical position where you want "Home" to be (e.g., against a known hard stop or alignment mark).

Record Machine Position: Check the "Machine" coordinate display. This value (the difference) is your new Grid Shift.

Update Parameter: Enter this value back into parameters 508 or 511. Note: A positive shift moves the home position in the positive direction. 3. Solving Common Homing Errors

If you are struggling with homing accuracy or the machine refuses to reference: FANUC Second Reference Point - CNCmakers

Before any changes can be made, you must unlock the system's ability to write to parameters.

PWE (Parameter Write Enable): To change most parameters, set the control to MDI mode and change the PWE bit to 1.

E-Stop: Some machines require the Emergency Stop button to be depressed before parameters can be successfully modified.

P Can / P Cancel: Use this procedure to bypass soft limit alarms when re-establishing zero reference by holding P and CAN during power-up. 2. Core Reference & Axis Parameters

These parameters define how the machine identifies its "home" and coordinate space.

Zero Reference (Parameter 1815): For systems with absolute encoders:

Bit #4 (APZ): Setting this bit to 1 establishes the current position as the machine's zero/home position.

Bit #5 (APC): Determines if an absolute pulse coder is used.

Soft Limits (Parameters 700–703): These define the travel limits for each axis. If the machine "homes" too early or crashes, these values may be incorrect.

Grid Shift (Parameters 508–511): Used to fine-tune the reference position after a physical limit switch is hit. It allows for adjustments within one revolution of the encoder. Reference Points:

1241: Coordinate value of the second reference point (G30 P2). 1242: Coordinate value of the third reference point. 3. Critical Option Parameters (900 Series)

The 900-series parameters are "bits" that enable specific machine features. These are typically provided by the machine tool builder (MTB) and must be backed up, as losing them can disable entire functions.

Unlocking the Full Potential of Your FANUC System: Understanding and Utilizing OT Reference Parameters for Enhanced Performance

In the world of industrial automation, FANUC has established itself as a leading provider of cutting-edge robotic and CNC solutions. With a wide range of products and applications, FANUC systems are used across various industries, from manufacturing and assembly to machining and processing. One key aspect that sets FANUC apart is its emphasis on precision, reliability, and flexibility. A crucial element in achieving these goals is the use of OT (Operator) reference parameters. In this article, we will delve into the significance of OT reference parameters, explore their benefits, and provide guidance on how to better utilize them to optimize your FANUC system's performance.

What are OT Reference Parameters?

OT reference parameters are a set of predefined values and settings used in FANUC systems to control and regulate various aspects of machine operation. These parameters serve as a reference point for the system's operational characteristics, such as movement, speed, acceleration, and deceleration. By adjusting and fine-tuning these parameters, operators and programmers can tailor the system's behavior to suit specific application requirements, ensuring optimal performance, and accuracy.

The Importance of OT Reference Parameters For a Fanuc 0T control, improving or resetting

OT reference parameters play a vital role in achieving precise and consistent results in FANUC-based applications. Here are some key reasons why these parameters are essential:

Improved Accuracy: By setting precise OT reference parameters, you can ensure that your FANUC system operates with high accuracy, reducing errors and deviations.
Enhanced Performance: Optimizing OT reference parameters enables your system to perform at its best, resulting in increased productivity, and reduced cycle times.
Increased Flexibility: With a deep understanding of OT reference parameters, you can adapt your FANUC system to changing application requirements, making it easier to reconfigure and reprogram.
Better Machine Protection: Properly set OT reference parameters help prevent machine damage, wear, and tear, reducing maintenance costs and downtime.

Common OT Reference Parameters

Some of the most commonly used OT reference parameters in FANUC systems include:

Acceleration and Deceleration Rates: These parameters control how quickly the machine accelerates and decelerates, affecting overall performance and accuracy.
Speed and Velocity Limits: These parameters set the maximum speed and velocity of the machine, ensuring safe and efficient operation.
Positioning and Orientation: These parameters determine the machine's positioning and orientation accuracy, critical in applications such as assembly and machining.
Torque and Force Limits: These parameters regulate the machine's torque and force output, protecting against overload and damage.

Best Practices for Utilizing OT Reference Parameters

To get the most out of your FANUC system, follow these best practices when working with OT reference parameters:

Consult the System Manual: Familiarize yourself with the system's documentation and guidelines for setting OT reference parameters.
Start with Default Values: Begin with the default parameter settings and adjust them as needed for your specific application.
Test and Validate: Thoroughly test and validate your parameter settings to ensure optimal performance and accuracy.
Monitor and Adjust: Continuously monitor your system's performance and adjust OT reference parameters as needed to maintain optimal operation.

Tips for Better Utilizing OT Reference Parameters

To take your FANUC system to the next level, consider the following tips:

Use Parameter Backup and Restore: Regularly backup your parameter settings and restore them as needed to prevent data loss and ensure consistency.
Take Advantage of Automatic Parameter Tuning: Some FANUC systems offer automatic parameter tuning features; leverage these to optimize performance and reduce manual effort.
Leverage FANUC's Software Tools: Utilize FANUC's software tools, such as FAS (FANUC Application Software), to simplify parameter management and optimize system performance.
Stay Up-to-Date with System Updates: Regularly update your FANUC system to ensure you have the latest features, improvements, and parameter settings.

Conclusion

In conclusion, OT reference parameters play a vital role in unlocking the full potential of your FANUC system. By understanding and utilizing these parameters effectively, you can optimize performance, accuracy, and flexibility, while reducing errors, wear, and tear. By following best practices, tips, and guidelines outlined in this article, you can take your FANUC system to the next level, achieving better results, and improving overall productivity. Whether you're a seasoned programmer or an operator, mastering OT reference parameters will help you get the most out of your FANUC investment.

FAQs

What are the most common OT reference parameters used in FANUC systems? Common OT reference parameters include acceleration and deceleration rates, speed and velocity limits, positioning and orientation, and torque and force limits.
How do I access and modify OT reference parameters on my FANUC system? Refer to your system's manual and documentation for instructions on accessing and modifying OT reference parameters.
Can I use the same OT reference parameters across different FANUC systems? No, OT reference parameters are specific to each system and application; ensure you consult the relevant documentation and guidelines for your particular system.

By applying the knowledge and insights shared in this article, you'll be well on your way to becoming an OT reference parameter expert, optimizing your FANUC system's performance, and achieving better results.

Mastering the Fanuc 0T reference parameters is the difference between a machine that just "runs" and one that operates with peak precision. Whether you are recovering from a battery failure or fine-tuning for high-accuracy machining, understanding how to manipulate these hidden system variables is essential. The Core of Fanuc 0T Reference Parameters

Reference parameters, often called "homing" parameters, define the machine's absolute zero point. If these are slightly off, your tool offsets and soft limits will be incorrect, potentially leading to crashes or scrapped parts.

Parameter 0003 (ZMx): Sets the reference position return direction for each axis (X, Z, and any additional axes).

Parameters 0700–0707: Define the stored stroke limits (soft limits). These must be set relative to a correctly established reference position to protect the machine from over-travel.

Grid Shift (Parameters 0508–0511): These allow you to "shift" the reference point by a specific amount without moving the physical home switches. How to Optimize for "Better" Performance

To get "better" results from your Fanuc 0T, you must look beyond the standard home cycle and optimize the interaction between the servo system and the control interface. Fanuc Soft Limit Parameter Guide | PDF - Scribd

To improve the Fanuc 0T reference parameter feature, you need to correctly configure the parameters that define the machine’s "Home" position. This process typically involves enabling specific bits and setting coordinate values for the machine to recognize its zero point. 1. Enable Parameter Write (PWE)

Before making changes, you must allow the control to accept new data: (Parameter Write Enable) and change it from

Note: The machine will likely trigger a "P/S 100" alarm, which is normal when PWE is active. Machine Metrics 2. Set Reference Point Parameters

The following parameters are critical for defining and troubleshooting the reference (Home) position on a Fanuc 0T control: Parameter 22 (Reference Set Bits): Used to manually force a reference point for specific axes. X-axis reference. Y-axis (if applicable). Parameter 0003 (Direction):

Sets the direction of the reference position return (Positive or Negative). Parameters 708 & 709 (Work Coordinate Setting): On older 0T models, setting Parameter 10.7

will use these values to automatically set the Work Coordinate System upon a manual reference return. X-axis value. Z-axis value. Parameters 700–706 (Travel Limits):

If you are unable to reach the reference point because of an overtravel alarm, you can temporarily increase these values (e.g., to ) to allow the axis more travel room during setup. 3. Procedure for Absolute Encoders

If your machine uses absolute encoders and has lost its zero position (common after a battery failure):

Jog the machine to the physical position you want to call "Home". Parameter 22 and set the bit for the relevant axis (X, Y, or Z) to

Cycle the machine power off and on to finalize the new reference position. 4. Verification and Safety

Series 0 / 00 / 0-Mate for Lathe - Parameter Manual - Drivesul

The phrase "deep feature" in the context of a Fanuc 0T control typically refers to advanced diagnostic or "hidden" parameters used to fine-tune axis performance, specifically regarding Reference Point Return (Zero Return).

On a Fanuc 0T, the "better" or more precise reference position is often achieved by adjusting the Grid Shift and Reference Position Shift parameters rather than physically moving limit switches. 1. Key Reference Parameters

To refine the zero position on a Fanuc 0T, you primarily work with the following:

Parameter 0508 – 0511 (Grid Shift): This is the most common "deep" adjustment. It allows you to shift the electrical zero point relative to the encoder's marker pulse (one-rotation signal).

Parameter 0708 – 0711 (Reference Position Shift): Used to adjust the coordinate value of the reference point without moving the physical stop.

Parameter 0021 – 0024 (Reference Position Amount): Defines the distance from the machine zero to the reference point. 2. Improving "Better" Reference Accuracy

If you find your machine "drifts" or the zero position is inconsistent, check these "deep" settings:

Deceleration Dogs: Ensure the physical cam (deceleration dog) is clean. The 0T looks for the deceleration signal first, then the next encoder grid mark.

Reference Speed (Parameter 0518 – 0521): If the zero return procedure is performed too fast, the axis might overshoot the grid pulse, causing a one-turn error. Reducing the rapid rate for reference return can improve consistency.

Backlash Compensation (Parameter 0535 – 0538): If the machine has mechanical play, the reference point may appear to shift. Adjusting backlash parameters ensures the axis settles in the same spot every time. 3. Setting a Second Reference Point Precision control : The FANUC OT reference parameter

For tool changes or specific parking spots, you can use the following to set secondary "better" positions:

Parameter 0704 – 0707: These define the coordinate values for the 2nd reference point (G30 P2).

Pro-Tip: Always back up your parameters before changing 500-series or 700-series data, as these are critical to the machine's physical geometry.

The FANUC 0T (Zero T) control system is a staple of CNC lathe automation, renowned for its reliability and longevity. At the heart of its precision and adaptability lies its parameter system, specifically the reference parameters. These parameters act as the DNA of the machine tool, dictating everything from axis movement limits to communication protocols and canned cycle behaviors. Understanding, accessing, and modifying these parameters is a critical skill for CNC technicians and engineers tasked with machine optimization, troubleshooting, and retrofitting. The Role of Reference Parameters in FANUC 0T

Parameters in the FANUC 0T system are numerical values stored in the CNC’s memory that define the specific operating environment of the machine. Because the 0T control was designed to be used across a wide variety of lathe brands and configurations, the control itself is highly generic upon leaving the factory. It is the reference parameters, usually set by the Machine Tool Builder (MTB), that customize the control to match the physical mechanics of a specific lathe. These parameters govern several critical domains:

Axis Control and Grid Shifts: Defining rapid traverse rates, acceleration/deceleration curves, and reference point (home) positions.

Spindle Control: Setting maximum spindle speeds, gear ranges, and orientation.

System Diagnostics: Enabling or disabling specific options, such as custom macro B, thread cutting cycles, or specific canned cycles (like G70-G76).

I/O Communications: Configuring baud rates, stop bits, and protocols for RS-232 serial communication with external computers (DNC). Accessing and Modifying Parameters

Modifying parameters on a FANUC 0T control requires a strict sequence of operations to prevent accidental changes that could render the machine inoperable or unsafe. Safety protocols dictate that these changes should only be made when the machine is in a safe state, preferably in an emergency stop condition or in MDI (Manual Data Input) mode.

The standard procedure for modification involves the following steps:

Enable Parameter Write: On the setting screen (accessed by pressing the SETTING or DGNOS/PARAM button), the operator must locate the "PARAMETER WRITE" (PWE) setting. Changing this value from 0 to 1 enables the control to accept changes to the parameter memory. This action usually triggers a P/S 100 alarm, which is a normal warning indicating that parameter writing is enabled.

Navigate to the Specific Parameter: By pressing the PARAM key, the operator can scroll or use the search function to input the specific parameter number they wish to view or edit.

Key in the New Value: Once the target parameter is highlighted, the new value is keyed in and entered using the INPUT button.

Disable Parameter Write: After the modifications are complete, the operator must return to the setting screen and change the "PARAMETER WRITE" (PWE) back to 0.

Power Cycle: Many critical reference parameters do not take effect immediately. The control must be powered down and restarted to load the new values into the active system memory. Critical Parameter Categories for the 0T Control

While thousands of parameters exist, several key categories are frequently referenced during maintenance and setup: 1. Communication Parameters (The 0000 and 0200 Series)

To transfer programs via RS-232, the control must match the settings of the external computer. Parameter 0002 typically sets the device type and communication channel, while parameters in the 0250 and 0500 range often dictate the baud rate (e.g., setting a value of 10 or 11 to achieve 4800 or 9600 baud). 2. Axis and Pitch Error Compensation

Parameters in the 0500 and 0700 series are often used to compensate for mechanical inaccuracies. Leadscrew pitch error compensation values are stored here, allowing the control to adjust the commanded position to account for physical wear in the ball screw, ensuring micron-level accuracy. 3. Reference Point Return (Grid Shift)

Parameters like 0508 through 0511 (depending on the specific sub-model of the 0T control) are used for grid shift. When a machine is crashed or a physical limit switch is moved, the home position (G28) may no longer align with the machine's physical zero. Adjusting the grid shift parameter shifts the electronic reference point without needing to physically move mechanical switches. Best Practices and Precautions

The power to modify reference parameters comes with significant risk. An incorrect value in a rapid traverse parameter can cause a catastrophic machine crash. A misplaced bit in a system option parameter can disable critical machine functions.

Consequently, strict adherence to best practices is mandatory:

Always Backup First: Before changing a single bit, a complete backup of the existing parameters (and diagnostic parameters) must be downloaded to an external PC or physically written down.

Consult the MTB Manual: While FANUC provides the control, the Machine Tool Builder provides the specific parameter list mapped to that specific machine. Always cross-reference FANUC manuals with the lathe builder’s documentation.

One Change at a Time: When troubleshooting, change only one parameter at a time and test the result. Modifying multiple parameters simultaneously makes it impossible to isolate the variable that solved or caused a problem. Conclusion

The reference parameters of the FANUC 0T control system are the bridge between the digital logic of the CNC and the physical reality of the machine tool. They provide the flexibility that has allowed the 0T control to remain relevant and functional decades after its introduction. For the CNC professional, a deep understanding of these parameters is not just an asset—it is a requirement for unlocking the full potential, precision, and longevity of the machine.

Informative Report: FANUC Series 0-T Parameter Reference and Optimization

Subject: Understanding and Optimizing FANUC 0-T Reference Parameters Date: October 26, 2023 To: CNC Maintenance Personnel, Machine Tool Operators, and Plant Managers From: Technical Services Division

Conclusion

The effective utilization of FANUC OT reference parameters is key to unlocking the full potential of CNC machines. By understanding their significance, properly managing them, and following best practices for optimization, manufacturers can significantly enhance machine performance, efficiency, and reliability. As technology continues to evolve, staying informed and adaptable will be crucial for leveraging the advanced capabilities of CNC systems like those offered by FANUC.

Case Study: Improved Efficiency through Parameter Optimization

A manufacturing plant using FANUC OT CNC machines for producing automotive parts was facing challenges with long cycle times and occasional inaccuracies. By reviewing and optimizing the reference parameters, the plant was able to:

Reduce cycle times by 15% through optimized axis movement speeds and improved tool change procedures.
Achieve a 20% decrease in part rejections due to enhanced precision and accuracy settings.

Technical Report: Analysis and Configuration of Reference Point Parameters for Fanuc OT Control

Date: 2024-05-XX System: Fanuc OT (Model A / B / C) Subject: Reference Position Return Parameters (#000, #001, #002, #003, #508, #509)

2.3 Absolute Encoder Parameters (Nos. 508 & 509) – For Battery-Backed Systems

If the machine uses absolute encoders (no dog required), parameters 508 & 509 store the master reference position.

| Parameter | Axis | Function | | :--- | :--- | :--- | | 508 | X | Absolute reference position (low word) | | 509 | Z | Absolute reference position (high word combined with 508) |

How to set after battery replacement:

Manually move axis to desired machine zero (using dial indicator or scribe mark).
Set parameter 1815 (if available on OT C) – Note: OT A/B often lacks 1815; use procedure via PWE and power cycle.
For pure OT A/B without 1815: Set PWE=1, set parameter 508/509 to 0, power off. Then set desired value via absolute encoder setup procedure (reference manual B-61813E).

Phase 5: Deceleration Feedrate (Parameters 0700-0703)

A common frustration is a machine that slams into the deceleration dog. You set the ref point, but homing sounds like a car crash. Fix this with Param 0700 (X) and 0701 (Z).

Default is usually 300 mm/min.
Better setting: Reduce to 100-150 mm/min for the deceleration stage. This gives the encoder a clearer marker pulse and reduces wear on the limit switch dogs.
Caution: Do not set the deceleration feedrate to 0. The machine will not move.

Case Study: The "DR Off" Nightmare

Scenario: Your Fanuc OT lathe shut down over the weekend. Batteries died. Monday morning, you power up and get "DR Off" (Dead Recoil Off) or "Not Ready."

The Wrong Way: Guess the reference point, set it blindly, and crash the turret into the chuck.

The Better Way (Fanuc OT Reference Parameter Recovery):

Bypass the alarm: Hold P + CAN while powering on.
Set PWE 0000 to 1.
Move to safe position: Jog the X axis to mid-stroke, Z axis to mid-stroke.
Set Parameter 85 and 86 to 0 (temporary). This tells the control "you are at home."
Cycle power. The machine now thinks mid-stroke is home.
Fine adjustment: Jog to the real physical home (use the physical scribe marks on the casting). Record the machine coordinates. Subtract 5mm for safety. Enter those numbers into Params 85/86.
Test the soft limits: After resetting, try to jog toward the chuck. The soft limit (OT) should stop you 5mm before collision. If not, adjust Params 85/86.