Cause : External Error comes when a a digital input that has been configured as "Ext Error assign" ETF is at active state. This means an external device connected to the drive has triggered the fault.

"EPF1" External detected fault on a Schneider ATV950 drive indicates that an external device or condition has triggered a fault signal to the drive. This fault can be caused by various external factors, including sensors, external protection devices, or signals from other connected equipment.

Steps to Address "EPF1 External Detected Fault":

1. Immediate Actions:

   • Stop Operation: If the drive is running, stop it to prevent any potential damage or unsafe conditions.
   • Reset Fault: Attempt to reset the fault using the drive's control panel or through the connected control system. This can sometimes clear temporary issues.

2. Identify External Source:

   • Connected Devices: Identify all external devices and sensors connected to the drive that could trigger an external fault.
   • Fault Signal: Determine which device or signal triggered the fault. This may involve checking the wiring and connections to identify the source.

3. Inspect External Devices:

   • Sensors: Check any external sensors (e.g., temperature, pressure, flow) for proper operation. Ensure they are within their operating ranges and not malfunctioning.
   • Protection Devices: Inspect external protection devices (e.g., overload relays, circuit breakers) for tripping or faults.
   • Interlocks: Verify that any safety interlocks or emergency stop circuits are in a normal condition and not activated.

4. Check Wiring and Connections:

   • Connections: Ensure that all wiring and connections between the drive and external devices are secure and free from damage.
   • Signals: Check that all external fault signals are correctly wired and not causing false alarms.

5. Review Configuration Settings:

   • External Fault Settings: Check the drive's configuration settings related to external fault detection. Ensure that the parameters are correctly set for the connected external devices.
   • Thresholds: Verify that any thresholds or limits set for external fault detection are appropriate for the application.