BUS-OFF state of the system bus (CAN)

What does it mean?

The controller has received too many faulty telegrams via the system bus (CAN) and has disconnected from the bus.

Common causes

• Too many faulty telegrams on the system bus (CAN) — bus termination, cable shielding or PE connection issues
• possibly also a high bus load.

How to fix it

• Check the bus termination at X4, cable shielding and PE connection
• reduce the baud rate if necessary (mind the cable length).

After troubleshooting: de-energise the device completely (disconnect the 24 V supply and discharge the DC bus) before opening the covers.