The RS485 communication port is a hardware description of communication ports. The wiring mode of the RS485 port is in the bus topology, and a maximum of 32 nodes can be connected to the same bus. In RS485 communication network generally adopts the master-slave communication mode, that is, a host with multiple slave. In most cases, rS-485 communication links are simply connected to the “A” and “B” ends of each interface with A pair of twisted pair cables. This data transfer connection is a half – duplex communication mode. A device can only send or receive data at a given time. After the hardware communication interface is established, a data protocol needs to be agreed between the data transmission instruments so that the receiving end can parse the received data, which is the concept of “protocol”. The communication protocol has a unified standard protocol format, and our products all use the standard Modbus-RTU protocol. Rs-485 maximum communication distance is about 1219m, in low speed, short distance, no interference occasions can use ordinary twisted-pair line, on the contrary, in high speed, long line transmission, it must be used impedance matching (generally 120 ω) RS485 special cable, and in the harsh interference environment should also be used armoured twisted-pair shielded cable.
Post time: Jul-22-2022