What is CAN bus error
CAN bus error can be caused by several reasons. CAN Frame error, faulty cable, noise, malfunction of each nodes, โฆ SO identify and classfy these errors are key to ensuring performance of the overall CAN system.
How does CAN error handling work?
1. CAN node 1 transmits a message onto the CAN bus - and reads every bit it sends
2. In doing so, it discovers that one bit that was sent dominant was read recessive
3. This is a 'Bit Error' and node 1 raises an Active Error Flag to inform other nodes
4. In practice, this means that node 1 sends a sequence of 6 dominant bits onto the bus
5. In turn, the 6 dominant bits are seen as a 'Bit Stuffing Error' by other nodes
6. In response, nodes 2 and 3 simultaneously raise an Active Error Flag
7. This sequence of raised error flags comprise part of a 'CAN error frame'
8. CAN node 1, the transmitter, increases its 'Transmit Error Counter' (TEC) by 8
9. CAN nodes 2 and 3 increase their 'Receive Error Counter' (REC) by 1
10. CAN node 1 automatically re-transmits the message - and now succeeds
11. As a result, node 1 reduces its TEC by 1 and nodes 2 and 3 reduce their REC by 1