Fanuc Wn57 Override Function Is Active 'link' May 2026

Fanuc WN57 Override Function Is Active

Overview The message "WN57 override function is active" indicates that one or more feedrate or spindle override functions are currently enabled on a FANUC CNC control. This is a status/notification describing that the machine will not run at the programmed nominal feed or spindle speed because operator overrides are modifying those values in real time.

What it means

• Override active: The control is applying an operator-set multiplier (override) to feedrate and/or spindle speed. The program runs but actual motion or spindle RPM differs from programmed values.
• Common override types: Feedrate override, spindle speed override, rapid traverse override, and jog override. WN57 typically refers generically to override-state reporting rather than a fault.
• Effect on machining: Parts may cut faster or slower, surface finish and tool life can change; motion interpolation and canned cycles still execute but scaled by override percentages.

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. fanuc wn57 override function is active

Example Troubleshooting Scenario

• Symptom: WN57 appears and feedrate limited to 50%.
  1. Check message — shows “WN57 Watchdog override active”.
  2. Inspect PLC comms — observe Ethernet link lost last minute.
  3. Restore network, reset control; WN57 clears and full feed returns.
  4. Root cause: intermittent network cable; replaced cable and secured connections.

Part 6: Preventive Measures – How to Avoid WN57 Forever

Best practice for operators:

1. Develop a "Shutdown Checklist" Before switching from MEM to EDIT (or vice versa), mentally scan: Fanuc WN57 Override Function Is Active Overview The

   • Dry Run off?
   • Single Block off?
   • Machine Lock off?
   • Block Search completed?

2. Leverage the "Condition" Display Screen On FANUC 0i-D and later, press the [SYSTEM] button, then the [CONDITION] soft key. This displays a live status of all overrides (MLK, DRY, SBK, AUX). Make this your default screen during setup.

3. Use G-Code to Automate Cancellation At the end of all your test programs, include: Override active: The control is applying an operator-set

   M00 (PAUSE) ; Optional stop
   #3000=1 (CHECK OVERRIDES OFF) ; Custom macro stop
   

   This forces the operator to hit RESET and disable overrides.

4. Machine Builder Configuration (Advanced) If you are a machine tool builder, consider modifying the ladder logic so that WN57 appears as a pop-up dialog with instructions (e.g., “Turn MLK off on panel OPR07”), rather than a cryptic message.