The Difference Between CAN Bus and 485 Bus
The difference between CAN bus and 485 bus lies in different principles, different communication methods and different characteristics.
1. Principle:
CAN bus: The two output terminals CANH and CANL of the CAN transceiver interface chip 82C250 are connected to the physical bus, and the state of the CANH terminal can only be a high level or a floating state, and the CANL terminal can only be a low level or a floating state.
485 bus: adopts balanced transmission and differential reception, so it has the ability to suppress common mode interference. In addition, the bus transceiver has high sensitivity and can detect voltages as low as 200mv, so the transmission signal can be recovered from kilometers away.
2. Support communication methods
The CAN bus controller area network effectively supports the serial communication network of distributed control or real-time control.
The 485 bus adopts half-duplex working mode and supports multi-point data communication.
3. Features
CAN bus has become the standard bus of automotive computer control system and embedded industrial control local area network, and has the J1939 protocol specially designed for large trucks and heavy industrial machinery vehicles with CAN as the underlying protocol.
485 bus: a bus-type structure with terminal matching. That is, a bus is used to connect each node in series, and a ring or star network is not supported.
