Earth Switch fault

What does F85 mean?

This fault is triggered by a digital input fault, indicating an issue with the earth switch. This suggests the earth switch may be in an incorrect state or its monitoring circuit has an error.

• Physical earth switch (e.g., maintenance earthing switch) is in the closed (earthed) position, preventing drive operation due to safety interlock.
• Auxiliary contact on the earth switch has failed mechanically or electrically (e.g., stuck open/closed), providing an incorrect state signal to the drive's digital input.
• Wiring fault (e.g., open circuit, short to 0V) in the control circuit from the earth switch auxiliary contact to the drive's digital input (e.g., DI8).
• Accumulation of dust or debris on the earth switch auxiliary contacts causing intermittent connection or false signaling.
• Incorrect configuration of the digital input parameter (e.g., P3-12 for DI8) expecting an incorrect logic state (normally open vs. normally closed) from the earth switch.

Click steps to track your progress.

1. 1

   1. Visually confirm the physical position of the earth switch. Ensure it is fully in the OPEN (de-earthed) position if drive operation is intended.

2. 2

   2. Using a multimeter, test the continuity of the earth switch's auxiliary contacts. Verify that the contacts change state (open/closed) reliably when the main switch is operated.

3. 3

   3. Check the wiring integrity from the earth switch auxiliary contacts to the designated digital input terminal on the drive (e.g., DI8). Measure voltage at the digital input terminal relative to 0VDC.

4. 4

   4. Access the drive parameters and verify that the digital input function (e.g., P3-12) and its logic (normally open/closed) are correctly configured to match the earth switch's auxiliary contact type.

5. 5

   5. Inspect and clean the auxiliary contacts of the earth switch for any dust, corrosion, or foreign material that might impede proper contact operation. Cycle the switch several times.