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