EFB comm loss

What does 6681 mean?

A communication break has occurred in the embedded fieldbus (EFB) communication link. This means the drive has lost its connection with the fieldbus master, leading to a loss of control and monitoring capabilities via the EFB, which can halt automated processes.

• Physical disconnection or damage to the fieldbus cable (e.g., Ethernet, RS-485) between the drive and the fieldbus master (PLC, DCS).
• Incorrect fieldbus termination resistor (e.g., 120 ohms for RS-485) at either end of the bus or missing termination.
• Mismatch in fieldbus communication parameters (e.g., baud rate, data bits, parity, station address) between the drive and the master.
• Faulty embedded fieldbus (EFB) module within the drive, preventing proper communication.
• Power cycling of the fieldbus master or loss of power to the fieldbus segment.

Click steps to track your progress.

1. 1

   Inspect the fieldbus cable (e.g., CAT5e, shielded twisted pair) for physical damage, proper routing, and secure connections at both the drive and master.

2. 2

   Verify fieldbus communication parameters (e.g., P53.01 EFB address, P53.02 EFB baud rate) in the drive match the master controller's configuration.

3. 3

   Check the status LEDs on the drive's embedded fieldbus port (e.g., TX/RX, Link/Act LEDs) for activity and error indications.

4. 4

   Measure the voltage levels and signal integrity on the fieldbus cable (e.g., A/B lines for RS-485) using an oscilloscope if available.

5. 5

   Confirm that termination resistors (e.g., 120 ohms) are correctly applied at the physical ends of the fieldbus segment, if required.