R485 interface, MODBUS protocol for communication cables, is a few cores, how wiring?
Most of them are made of 2 core wires: A/+, B/- (preferably shielded twisted pair) shielded wire ground.These are possible when using the 4 core line:1. leave a pair of wires in reserve;2. add a pair of relay power lines;3. consider instead of RS422 full duplex communication. (some interfaces are compatible with 485 and 422422 and require 4 lines.)
Most of them are made of 2 core wires: A/+, B/- (preferably shielded twisted pair) shielded wire ground.These are possible when using the 4 core line:1. leave a pair of wires in reserve;2. add a pair of relay power lines;3. consider instead of RS422 full duplex communication. (some interfaces are compatible with 485 and 422422 and require 4 lines.)
RS485 is the port, and MODBUS is the protocol. He built communications on the basis that the RS485 was the terminal. So MODBUS cannot do without 485485 also cannot do without MODBUS first half of that is basically correct. (RS485 is the connection port (485) and also cannot do without MODBUS) the wrong answer is not entirely RS485 connection port, it is a kind of electrical standards, including mechanical properties, electrical properties and other characteristics, can find some communication look at the books, there are a lot of features described; 485 also cannot do without MODBUS, understanding is narrow, many with 485 communication protocols, MODBUS is one of commonly used a protocol, such as IEC103, CDT etc. are all RS485 communication mode, and a little MODBUS is not completely in RS485 communication mode, and TCP mode modbusplus has a detailed introduction.
