| Symptom | Likely cause | Action | |--------|-------------|--------| | WN57 only, machine runs fine | Override ≠ 100% | Accept or set all overrides to 100% | | WN57 + no cycle start | Builder lock active | Set all overrides to 100%, dry run OFF, then RESET | | WN57 appears after power-on | Stored override value | Reset control, check last active override | | WN57 + weird axis movement | Custom PMC override mode | Call machine tool builder |
Examples
Example 1 — First-piece slowdown
Example 2 — Rapid move reduction during setup
Example 3 — Spindle tuning during finish pass
Best practices
Troubleshooting
If you want, I can produce a short checklist tailored to your machine model (e.g., FANUC Oi-MF, 32i-A) showing exact keys/screens to inspect.
This Fanuc message indicates that a customized Override Function (WN57)
is currently active within the PMC (Programmable Machine Control) fanuc wn57 override function is active
, typically used to modify feedrates, rapid traversals, or spindle speeds specifically for authorized machine operations. Overview of Fanuc WN57 Override
Usually mapped to custom PLC/PMC logic to lock, limit, or force a specific override percentage, overriding the standard operator panel knobs. Operation:
When active, the feedrate or speed is dictated by the PMC logic rather than the physical operator panel dial. Where to Check: (PMC Maintenance) screens for the specific status of WN57. Potential Reasons for Activation Custom PMC Function:
A custom PMC function is currently running, often configured in the Robodrill or similar PMC-controlled machinery. Manual Intervention: Manual intervention occurred during an automatic cycle. System Macro Settings: System macro variable
may have been utilized to disable or set overrides programmatically. What to Do If Unintended Check Diagnostics: DIAGNOSTICS screen and look at status for (W-address 57) to determine if it is (Active) or (Inactive). Toggle Switch/Menu: Use the custom operator panel or softkey to disable the specific override function.
Press the [Reset] button to clear temporary custom PMC overrides.
For more tailored information, please verify if this is on a FANUC ROBODRILL OPERATOR'S MANUAL or a similar specialized machine.
FANUC Robodrill Operator's Manual | PDF | Direct Current - Scribd
WN57 OVERRIDE FUNCTION IS ACTIVE message on a FANUC control indicates that the PMC Override (forced I/O) function is currently enabled | Symptom | Likely cause | Action |
. This is a debugging feature used by technicians to manually force PMC signals during troubleshooting or ladder program setup.
While this function is active, the PMC may not behave as expected during normal machine operation. How to Disable the WN57 Message
To clear this message and return the machine to standard operation, you must turn off the override function: Via PMC Parameters Navigate to the PMC Setting screen on your FANUC control. Find the option for Override Effective Set this value to Restart the CNC to clear the alarm. Via Keep Relay (K-Address) Directly change the keep relay
. This bit typically controls whether the override function is enabled. Why This Happens
This status is often triggered when a user or technician is "forcing" I/O points to test logic without actually firing physical sensors or switches. On newer controls like the Series 30i/31i/32i, an
alarm may also appear if too many PMC paths (more than three) are being overridden simultaneously. Course Hero
On a Fanuc system, the message "Override function is active" (often associated with diagnostic or status signals like WN57) is an interesting safety and operational feature primarily designed to manage machine behavior when standard speed or feed constraints are being bypassed. Key Aspects of the Override Active Feature
Operational Awareness: When this function is active, it indicates that the machine's programmed feedrates or spindle speeds are being scaled by a manual selector or a software override. This is critical for operators to know if the machine is running at 100% of its programmed speed or a safer, reduced percentage (e.g., during Manual Handle Feed).
Safety Interlocks: In many Fanuc PMC (Programmable Machine Control) ladder designs, WN57 (or similar window markers) signals that a forced I/O or override mode is engaged. This can be used to prevent the machine from starting a cycle if the override is set too low (stalling the tool) or too high for a specific setup. For safety, stop the program (optional) before making
Forced I/O Override: In high-end models like the Fanuc 30i/31i/32i Series, an "override mode" for forced I/O allows developers to test machine logic without physical signals. An interesting technical limit is that this mode is typically restricted to three PMC paths simultaneously; exceeding this triggers an ER47 alarm.
Macro Variable Control: Speed and feed overrides can be dynamically disabled or locked via macro variables. If the override is disabled through a macro, the machine ignores the physical dial, which can lead to unpredictable speeds if the operator is not alerted by the "Override Active" status. Common Related Alarms
If the override settings are configured incorrectly or conflict with other system parameters, you might encounter:
ER47: Illegal Override Function Setting (too many PMC paths active).
0011: Feed Zero—occurs if the override dial is at 0% while a cutting command is issued. AI responses may include mistakes. Learn more
The WN57 message indicates that an Override Function (such as Feedrate Override, Spindle Override, or Rapid Traverse Override) is currently active while a specific prohibited operation (like a threading cycle or rigid tapping) is being attempted.
In simpler terms: The CNC is telling you, “I cannot run this cycle because someone has turned a knob (override) that I am not allowed to ignore right now.”
In these cases → ignore the warning.