Editing a system variable is not like editing a register. A single mistake can freeze your controller, require a controlled start, or even demand a full system restore. Follow this 5-step safety protocol:
Cause: The variable requires a specific software option (e.g., $WELD_TIMER requires ArcTool).
Solution: Check your robot’s installed options via MENU > STATUS > VERSION ID. If the option is missing, the variable does not exist.
While you need the official PDF for completeness, the following table provides a high-level reference to the most frequently accessed system variables. (Note: Variable names may vary slightly by software version.) fanuc robot system variables pdf
| Category | Variable Example | Description | Typical Use Case |
| :--- | :--- | :--- | :--- |
| Master/Control | $MASTER_ENB | Master enable flag | Check if robot has mastered position |
| | $SVINFO | Servo information status | Monitor torque and feedback |
| Program Execution | $MCR.$GENOVERRIDE | Global speed override (0-100%) | Modify robot speed from PLC via fieldbus |
| | $TP_DISABLE | Disable teach pendant operation | Lock out pendant during remote run |
| I/O Configuration | $DIN[n] | Digital Input status (n = rack/slot) | Read sensor state |
| | $DOUT[n] | Digital Output control | Turn on gripper or conveyor |
| | $AIN[n] / $AOUT[n] | Analog Input / Output | Read pressure sensors or control weld voltage |
| Motion & Path | $ACC[n] | Acceleration percentage for motion group n | Smoother starts/stops for fragile parts |
| | $JVLIMIT | Joint speed limit | Constrain axis rotation for safety |
| | $PARAM_GROUP.$COLL_GUARD | Collision Guard sensitivity | Disable collisions for force-sensitive tasks |
| Arc/Spot Welding | $ARC_WELD[1].$WELD_CURR | Target welding current | Dynamic weld parameter adjustment |
| | $SPOT_TOOL[1].$PRESS_DELAY | Pressurization delay for spot gun | Fine-tune electrode squeeze time |
| Network/Fieldbus | $PNODE_IO[1] | Profinet or EtherNet/IP mapping | Check communication status to PLC |
| KAREL & BG Logic | $BG_LOGICAL | Background logic enable | Turn on user-defined background tasks |
If you need the official FANUC system variables PDF, contact FANUC technical support or your local distributor with your controller model (e.g., R-30iB Plus, software version 9.xx). They can email you the correct manual number and download link. Editing a system variable is not like editing a register
Would you like a list of specific variable names for a common task (e.g., I/O mapping, mastering, or speed control)?
Title: A Comprehensive Analysis of FANUC Robot System Variables: Architecture, Classification, and Practical Application Title: A Comprehensive Analysis of FANUC Robot System
Date: October 26, 2023 Subject: Industrial Robotics / Controls Engineering Keywords: FANUC, R-30iB, System Variables, $PARAM, TP Programming, I/O Integration