Internal Control Circuit or Terminal Board Fault

What does Control Circuit Fault mean?

This fault indicates either a problem within the drive’s internal control circuit or an improper connection of the terminal board to the main control board. It suggests an internal hardware malfunction or an installation error that affects the drive's core functionality and control integrity.

• Loose or corroded connection between the drive's terminal board and the main control board, affecting signal integrity.
• Internal component failure on the control board (e.g., DSP, microcontroller, memory) due to age or stress.
• Damage to the terminal board itself, such as hairline cracks or failed components due to vibration or environmental stress.
• Short circuit or transient overvoltage on a control input/output (I/O) terminal, propagating to the control board.
• Electrostatic discharge (ESD) damage to sensitive control components during handling or installation.

Click steps to track your progress.

1. 1

   1. Power down the drive completely (wait for DC bus discharge) and physically reseat the terminal board onto the main control board, ensuring all connectors are firm.

2. 2

   2. Inspect the terminal board and main control board visually for any signs of burn marks, swollen capacitors, or damaged traces.

3. 3

   3. Check all external control wiring connected to the terminal strip for shorts to ground or phase using a multimeter (with power off).

4. 4

   4. Measure the internal control power supply voltages (if accessible and documented) according to the drive's service manual to confirm internal power integrity.

5. 5

   5. Try removing non-essential option cards or external I/O connections temporarily (after power down) to isolate if an external influence is causing the fault.

6. 6

   6. If the fault persists after all external checks, consider replacing the terminal board if available as a spare part, or replacing the entire drive unit.