External Fault (Input Terminal S8)

What does EF8 mean?

An external fault has been triggered at multi-function input terminal S8. This signifies that an external device connected to S8 has activated an alarm function, or there's an issue with the wiring or configuration of terminal S8. This fault will typically cause the drive to stop operation.

• Activation of the external fault input terminal S8 by a connected safety device (e.g., E-stop, safety gate switch) due to an unsafe condition.
• Broken wire or loose connection to terminal S8, causing the input to open (if configured as NC) or close (if configured as NO) incorrectly.
• Faulty external sensor or switch connected to S8, incorrectly sending a fault signal to the drive.
• Interference or transient voltage spike on the control wiring to S8, briefly activating the input.
• Incorrect setting of parameter H1-08 (S8 function selection) or other H1-xx parameters, assigning an unintended fault function to S8.

Click steps to track your progress.

1. 1

   Identify the specific external device connected to input terminal S8 that triggers the fault.

2. 2

   Using a multimeter, verify the voltage or continuity at terminal S8 relative to COM (common) when the external device is in its normal, non-fault state (e.g., 24VDC for NO, 0VDC for NC).

3. 3

   Inspect the wiring connection to terminal S8 and the external device for any breaks, loose terminals, or corrosion.

4. 4

   Manually actuate the external device (e.g., limit switch, pressure switch) and observe its contact status with a multimeter to confirm correct operation.

5. 5

   Review the drive's parameter H1-08 (S8 function) to ensure it is correctly configured for the desired input function and fault trigger logic (NO/NC).

6. 6

   Check for ground loops or inadequate shielding on the control wire connected to S8 if intermittent faults occur without clear external cause.