Design And Research Of Web Controller Based On Embedded PLC Module

In the 21 st century,human being has entered the era of computer industry.With the deepening industrialization of China and the world,the past traditional industrial control solutions have been gradually replaced by Programmable Logic Controller(PLC).With the increase of personal computers,cell phones and other intelligent terminal devices as well as the development and popularity of the Internet,embedded PLC modules,which have gradually become an important role in the field of industrial control,users need to be provided with a cross-platform monitoring and control means that are different from the traditional PLC configuration software.Web technology and HTTP protocol have some excellent features such as cross-platform,standardization and so on,so the use of Web technology can solve the problem that traditional PLC equipment can only be monitored through the corresponding configuration software.So that users can access and monitor the control module through the B/S mode.Based on the embedded PLC module,Web technology and HTTP network protocol can be used to build an embedded PLC module that supports Webs control in the industrial production field.This paper will firstly elaborate the technical background and practical significance of the subject,introduce the development of embedded PLC technology and the recent research of embedded Web technology in China and abroad,and clarify the research direction and content of the subject.The main work of this paper is shown as follows:(1)First this paper will analyze HTTP protocol,including the format of the protocol message,the content of the message and the communication process of HTTP protocol and other characteristics.Then based on the "embedded PLC module",we add HTTP protocol layer and embedded Web server function to it,to develop and design an embedded PLC module supporting Webs control.The main contents include the hardware circuit system design and software system design of the embedded PLC module supporting Webs control.For the hardware system design,this paper will focus on the chip model selection of the module,the addition of the Ethernet communication module and the PCB hardware circuit board design.For the software system,the detailed design is mainly shown by using flowchart,code and text description.This part of the paper will show the detailed process of data transmission between the embedded Web server and Web browser through HTTP protocol,including the message reception,message parsing,data processing and the return of processing results of HTTP protocol.(2)In order to support Webs control on the basis of the original embedded PLC module,so that users can monitor the controller module through the B/S mode,in addition to adding the HTTP protocol layer on the module and implementing the embedded Web server function,it is also necessary to use HTML,Java Script and other front-end languages and technology to design and develop a Web interface for monitoring the embedded PLC module.In addition to adding HTTP protocol layer to the module and implementing embedded Web server function,it is necessary to develop a Web interface for monitoring the embedded PLC module using HTML,Java Script and other front-end languages.In the cases of no configuration software being installed or cannot be installed due to system or equipment limitations,the user can access and monitor the module using a Web browser instead.(3)The functions of the embedded PLC module supporting Webs control are tested through experimental tests,including real-time monitoring of PLC registers by monitoring Web pages,ON/OFF operation of the registers individually by clicking the register icons,uploading PLC programs and sending the stop and start orders of PLC programs.The stability of the module is also verified through fault tolerance test and long time operation test.