Mainly different speeds and different applications. High-speed CAN system using hardwire is power type, the speed of 500kbps, control ECU, ABS, etc.; low-speed CAN is comfort type, the speed of 125Kbps, mainly control the instrument, anti-theft, etc..
And is widely used in industrial automation, ships, medical equipment, industrial equipment and so on. Fieldbus is one of the hotspots of technological development in the field of automation today, and is known as the computer LAN in the field of automation. Its emergence provides strong technical support for distributed control systems to realize real-time, reliable data communication between nodes.
Expanded Information:
The CAN bus is connected to the physical bus via the two outputs CANH and CANL of the CAN transceiver interface chip 82C250, whereas the status of the CANH terminal can only be high or suspended, and the CANL terminal can only be low or suspended. This ensures that there will not be a phenomenon in the RS-485 network that occurs when the system has an error.
Causes the bus to present a short circuit, which can damage some nodes. And CAN nodes in the case of serious errors with automatic shutdown of the output function, in order to make the bus on the other nodes of the operation of the unaffected, so as to ensure that there will not be like in the network, due to individual node problems, making the bus in the "deadlock" state.
Baidu Encyclopedia - CAN Bus