The alarm appears in the PMC alarm section of your FANUC control system, distinguishing it from CNC alarms, servo alarms, or spindle alarms.
Safety. If Machine Lock is on, the position display moves, but the actual table does not. Running a program normally would crash the tool. WN57 is a prevention alarm , not an error. It forces the operator to consciously acknowledge the override condition.
Make it a habit for operators to visually verify that all override dials are set to 100% before running a verified, production-ready CNC program.
When WN57 triggers, the CNC system detects that the override matrix—which governs the relationship between the programmed feedrate ( fanuc wn57 override function is active
✅ set to 100% when parameter has flagged that as “override active” ✅ Feed override knob set above 100% (if parameter enabled) ✅ Manual handle override (jog/handle multiplier in effect) ✅ Programmed override via PMC or G-code (e.g., G10.6 or G10.9 on some controls) ✅ Dry run + feed override combination tripping a builder-defined warning ✅ Machine builder’s custom PMC logic activates WN57 when any override ≠ 100%
Over time, the rotary potentiometers or digital switches on the FANUC operator panel can accumulate oil, coolant, or dust. This debris can cause electrical resistance fluctuations, tricking the CNC control into registering a 99% or 101% override value even if the physical dial appears centered at 100%. Operational Impacts of WN57
Navigate to the PMC or SYSTEM menu on your controller. The alarm appears in the PMC alarm section
The message persists as a safety precaution. If this function is left active after maintenance: The machine may behave unpredictably. Safety interlocks might be bypassed.
"The WN57 alarm is a serious machine fault requiring immediate service."
: It indicates that an override setting—such as Feedrate Override, Spindle Override, or Rapid Traverse Override—is currently engaged or forced. Running a program normally would crash the tool
The physical dial on the operator panel is not set to 100%.
A Keep Relay or parameter is forcing the machine to run at a reduced speed (e.g., during setup or dry run modes).