Host-slave station communication baud rate automatic matching

Abstract

The invention discloses host-slave station communication baud rate automatic matching, which comprises the following configuration steps of (1) appointing a group of baud rate through a host station and a slave station; (2) appointing 0xAA as a checking message through the host station and the slave station; (3) when electrifying the slave station, setting baud rate of a serial port as a default baud rate, waiting for receiving the checking message on a serial port bus, monitoring pulse width of a first byte, calculating the baud rate according to the pulse width if the messages received for continuous 3 times are not consistent to appointed checking messages, comparing the appointed baud rate and the calculated baud rate, and then selecting the proximate appointed baud rate as communication baud rate of the slave station. According to the host-slave station communication baud rate automatic matching provided by the invention, the automatic matching of the baud rates of the host station and the slave station is realized, and only few seconds to few minutes are needed for setting the baud rate for one time, so that the maintenance cost is reduced.

Description

technical field [0001] The invention relates to the technical field of electronics and communication engineering, in particular to automatic matching of communication baud rates of master and slave stations. Background technique [0002] The premise of serial port communication is that the communication devices have the same baud rate. The master-slave station serial port communication is a widely used communication protocol. It describes the process of a concentrator and protocol converter requesting access to other devices, and how to respond to requests from other devices. Device requests, and how errors are detected and logged. On the RS-485 bus, most of them adopt the master-slave communication mode, one host computer connects multiple slave stations. The communication between the host computer and the slave station mainly depends on the ID number of the slave station to identify, so that the master station can exchange data with the corresponding slave station. The p...

AI Technical Summary

Problems solved by technology

The premise of the communication between the master station and the slave station is that the baud rate of the master station and the slave station must be consistent. The existing technology mainly uses a dial switch to set the baud rate of each slave station or sets the slave station through software. As long as the baud rate of the master station is changed during use, the baud rate must be set for each device on the communication bus through the dial switch or software, which is very inconvenient to use, especially when the entire system is running After getting up, the communication is unstable. When it is necessary to change the baud rate of the bus, it will take a long time and seriously affect the use of the system.

[0003] For RS-485 bus communication, the communication baud rate of devices connected to the same bus must be the same. The existing RS-485 communication baud rate settings are all set through dial-up development, software or other methods, and need to be changed. The baud rate of the bus communication must be set for each device on the bus. There may be dozens of devices on a bus, and the distance between each device is tens to hundreds of meters, possibly thousands of meters. The whole system runs In the future, if the communication is unstable and it is necessary to reduce the communication baud rate to enhance the stability of the communication, it is necessary to stop the operation of the entire bus device, set it manually by dialing code development, software or other methods, and restart it after setting For the devices on the entire bus, this process takes tens of minutes to several hours, 1. Increases the maintenance labor cost of the entire system; 2. Stopping the operation of the entire bus device for tens of minutes to several hours will bring serious consequences to the entire system

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