Fanuc Wn57 Override Function Is Active [new] May 2026
This message—"WN57 OVERRIDE FUNCTION IS ACTIVE"—appears on FANUC CNC controls (often on series like 0i, 30i, 31i, 32i, or 21i) when the control is operating in a special override mode that bypasses certain safety or standard operating limits.
Below is a practical operator & setup guide to understanding, handling, and clearing this condition.
Step 1 – Check the actual override settings
- Rapid override – set to 100% (unless intentionally lower)
- Feed override – set to 100%
- Spindle override – set to 100% (less likely but possible)
- Dry run – turn OFF
The "WN" Code Explained
FANUC alarms are categorized by prefixes:
- SV (Servo Alarm): Issues with motors or drives.
- PS (Program/Sequence Alarm): Errors in G-code or macro syntax.
- SP (Spindle Alarm): Spindle drive or motor faults.
- WN (Warning): A non-critical condition that restricts operation but does not indicate hardware damage.
WN57 specifically belongs to a family of safety and interlock warnings. It translates to: “The control is currently in a state where manual or automatic override functions are engaged, preventing the requested action.” fanuc wn57 override function is active
Useful FANUC Screens to Check
- Alarm/Message window (top/right of display)
- System Alarm History
- I/O Status screen (Input/Output monitor)
- Servo/Drive Status (Amplifier/Alarm screens)
- Event Log / Operation History
- Parameters and OEM parameter blocks
- Macro variable monitor (to see active flags)
Step 2 – Reset the control
- Press RESET once (sometimes clears warning)
- If not cleared → cycle Emergency Stop (push in E-stop, then release)
- If still present → power off/on control (not always required)
Final recommendation
| Your goal | What to do | |-----------|-------------| | Just remove WN57 | Set rapid/feed override to 100%, dry run OFF, press RESET | | Run with override <100% | Ignore the warning if machine allows | | Machine refuses to run | Call machine tool builder – they set the logic | | You want to disable it | Check PMC ladder or FANUC parameter 3001#5 (OVW) |
If the machine is cutting correctly and no other alarms exist, WN57 is informational, not critical.
Title: Understanding FANUC WN57: "Override Function is Active" Step 1 – Check the actual override settings
Body:
If you are running a FANUC-controlled CNC machine and have encountered the WN57 alarm or status message stating "Override Function is Active," don’t panic.
This is not a critical machine failure, but rather a protective notification. Here is a breakdown of what it means, why it appears, and how to resolve it. Rapid override – set to 100% (unless intentionally
Part 7: Case Study – A Real-World WN57 Scenario
Machine: FANUC Robodrill α-D21MiB (31i-B control) Problem: Operator runs a warm-up program. Then turns on Dry Run to test a new engraving cycle. After testing, he edits the engraving program (Z-depth correction). He switches back to MEM and presses CYCLE START. Result: Alarm WN57 appears. Machine does nothing.
Troubleshooting:
- Operator checks physical panel – Dry Run switch is still ON (Orange LED).
- Operator turns Dry Run OFF.
- Operator presses RESET.
- WN57 remains on screen.
- Operator presses CYCLE START again (even though alarm is visible).
- The machine clears the alarm and starts moving.
Lesson Learned: On many FANUC 31i models, the CYCLE START button itself serves as the confirmation to exit "override active" state after the physical switch is turned off. Do not just reset – attempt cycle start.
Scenario 3: Handle Interrupt Mode
Some high-end FANUC models (31i-A, 31i-B) feature Handle Interrupt – a mode allowing the operator to manually jog an axis during an automatic cycle using the MPG (handwheel). If the operator exits this mode without canceling the interrupt or if the program expects synchronized axes, WN57 appears as a safety warning.