Option Communication Error

What does BUS Option Com Err mean?

After initial communication was established, the connection to the option board was lost. This indicates a broken connection or that the master controller stopped communicating, preventing data exchange.

• Loose or damaged ribbon cable connection between the drive's main board and the option board.
• Faulty or misconfigured option board causing it to drop off the communication bus intermittently.
• Master controller (e.g., PLC) stopping communication due to an internal fault or programming error, leading to bus timeouts.
• Excessive electromagnetic interference (EMI) on the control wiring disrupting digital communication signals.
• Incorrect communication protocol settings (e.g., baud rate in Parameter C6-01 or C6-02) between the drive and the option board.

Click steps to track your progress.

1. 1

   Safely power down the drive, then visually inspect the option board's physical connection and ribbon cable for damage or looseness; reseat the board securely.

2. 2

   Verify communication parameters (e.g., C6-01 for baud rate, C6-02 for data format) on the drive match the requirements of the option board.

3. 3

   Measure the resistance across communication bus termination resistors (e.g., 120 Ohms for RS485) if the option board uses an external bus connection.

4. 4

   Monitor communication activity using diagnostic tools (e.g., RX/TX LEDs on the option board or master) to pinpoint where data flow ceases.

5. 5

   Temporarily swap the option board with a known good unit to isolate whether the fault is with the board or the drive's main control unit.