External fault

What does 51 mean?

A digital input configured as an external fault has been triggered, indicating a fault condition in an external device connected to the drive. This causes the drive to trip, preventing further operation until the external fault is cleared. The specific external device must be identified and resolved.

• External safety circuit activation (e.g., E-stop, safety gate switch) connected to a digital input configured as a fault (e.g., P2-10 (DI1 function) set to "Fault").
• Overload or fault condition detected by an external motor thermal protector (PTC/NTC), causing its contact to open or close.
• Loose or broken wiring on the digital input terminal configured for external fault (e.g., DI3).
• Auxiliary equipment fault (e.g., pump dry-run, fan overtemperature) wired to trigger the drive's external fault input.
• Input signal noise causing momentary false triggering of the external fault input.

Click steps to track your progress.

1. 1

   Identify the specific digital input configured as an external fault (e.g., by checking P2-10 to P2-15).

2. 2

   Measure the voltage across the identified digital input terminal and its common (e.g., DI3 to 0V) to confirm its state.

3. 3

   Inspect the external device connected to this digital input for its operational status and any fault indicators.

4. 4

   Verify the wiring connections from the external fault device to the drive's digital input terminals (e.g., X1:1 to X1:4).

5. 5

   If the fault is intermittent, check for signal noise or transient voltages on the digital input line.

6. 6

   Reset the external fault condition on the external device before attempting to reset the drive.