Free networking method of RS485 communication terminal

Abstract

The invention discloses a free networking method of an RS485 communication terminal. A master station is in unidirectional semi-closed-loop serial connection with slave stations; the master station sends a networking command to a first slave station, starts overtime timing and waits for response information; after the first slave station receives the networking command, the first slave station takes the received slave station address as its own address, returns the response information, and adds one to its own address and sends the address to a next slave station; if correct response information is received in the overtime range of the master station, the received slave station address is stored, timing is restarted, and the response information of the next slave station is waited; after the next slave station receives the networking command, the next slave station takes the received slave station address as its own address, returns the response information, adds one to its own address and sends the address to a next slave station until the master station is overtime, and a networking finishing command is sent through an RS485, thus finishing the networking process. According to the method, the wiring is simplified; moreover, the address of each slave station can be allocated automatically, accurately and rapidly without manual intervention; the positions of the slave stations can be freely placed or replaced; and the debugging is efficient and convenient.

Description

technical field [0001] The invention relates to a method for free networking of RS485 communication terminals. Background technique [0002] RS485 communication has been widely used in the field of industrial control due to its simple development, low cost and strong anti-interference ability. There are two wiring methods: two-wire system and four-wire system. Full duplex communication. In the RS485 communication network, the master-slave communication mode is generally adopted, that is, one master has multiple slaves. [0003] When the RS485 communication network adopts the half-duplex communication mode, only one terminal (master station or one of the slave stations) occupies the bus at a certain moment, that is, only one terminal can send information at a certain moment, and the other terminals can only receive information. When the addresses of the slave stations are the same, the information sent by the master station responds from multiple slave stations at the same...

AI Technical Summary

Problems solved by technology

[0005] Obviously, the first three methods require manual intervention and are not convenient for on-site operation. The fourth method is time-consuming and seriously affects the communication efficiency of the RS485 communication port. The fifth method cannot place and replace the slave stations freely, which seriously affects Convenience of on-site operation

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