Electronic – How does Ethernet to CAN conversion work

canconverterethernet

I am wondering how an Ethernet-to-CAN converter works. CAN is a multi-master broadcasting network where messages are associated with IDs. Each message type has a unique ID. Devices listen to all messages on the bus and decide whether an ID is of interest. Ethernet, however, uses point-2-point addressing, meaning that sender and receiver are specified. These information cannot be mapped on CAN, because there is not sender or receiver field.

Let's say, device A sends message m to device B. Device B is connected via CAN to the converter. Device A communicates over Ethernet.

  1. How does the CAN-to-Ethernet converter select the message ID when converting an Ethernet frame to a CAN fame? Are the same CAN IDs used for packets to the same recipient?

  2. How does the CAN-to-Ethernet convert a CAN message to an Ethernet frame? A CAN message has no recipient, but an Ethernet frame knows the recipient address. How does the mapping work?

Best Answer

It varies as per product manufacturer but generally speaking,

CAN-to-ETH converter reads all the messages from CAN Bus, packs every message as payload of ethernet datagram and sends it to computer. This payload contains CAN message ID, DLC and data.

On Computer, you can configure to filter out messages as per your requirements. Usually a DLL is provided and you can build your own application. Some even provide application where you can monitor the bus.

We use CAN-ETH converter from ProconX. Their user manual contains this simple diagram which will help you to understand: CAN-ETH Protocol description

Again, it depends on manufacturer and you can find details in the manual.