Research And Development Of Embedded PLC Module Supporting Mitsubishi Communication Protocol Based On Ethernet Transmission

With the further development of industrialization in China,the traditional industrial control scheme has become more and more difficult to meet the needs of contemporary industrial production.In the modern industrial control system,the demand of equipment interconnection is becoming more and more prominent,and the establishment of large multi-node control system based on Ethernet has gradually become an important trend of industrial control system.Therefore,as an important role of industrial control,the embedded PLC module is very necessary to have the ability to set up a multi-node control system based on Ethernet.The standard MITSUBISHI communication protocol is an important and open communication protocol.The embedded PLC module can make use of this protocol to provide communication basis for building multi-node embedded PLC module control system based on Ethernet.This paper will firstly carry out background research and significance of the selected topics which introduce the research status of embedded PLC and PLC communication technology at home and abroad.Therefore it can determine the research direction and content of this topic.The main work of this paper is as follows:(1)The standard Mitsubishi data communication protocol is analyzed in detail,including the format of the protocol message,the function of the message and the characteristics of the packet during communication.Then based on the basis of the original "embedded PLC module ",the embedded PLC module based on Ethernet to support the Mitsubishi communication protocol is designed and developed,mainly including the hardware circuit system and software system design of the embedded PLC module.For the design and development of hardware system,this paper mainly introduces the chip model selection of embedded PLC module and the design of hardware circuit.It focuses on the design of wired and wireless Ethernet circuit of embedded PLC module,and develops the PCB board of embedded PLC module based on Ethernet supporting Mitsubishi communication protocol.For the software design part,this thesis mainly uses the flow chart method to explain the software design need to deal with the problem and the solution.In order to adapt to the network construction ofembedded PLC module,Mitsubishi data communication protocol needs to be extended.It also includes the following contents: Ethernet data receiving,Ethernet data analysis and Mitsubishi communication protocol packet response.(2)In order to meet the needs of testing embedded PLC module,building network,module status and program maintenance,this project develops client and server software of C/S mode based on an interface development software qt5.7.0,and uses them and the embedded PLC module of this project to build a multi-node joint control system based on Ethernet.(3)This paper describes the test of embedded PLC module,mainly divided into embedded PLC module single module test and component C/S mode network control system test.When the C/S mode network control system is set up,the server synchronizes the state value of the M register of each module,so as to realize the joint control function of the system by changing the state value of the operable M register of each module.Finally,the interface diagram of monitoring register,the physical test diagram and the text description of test results are integrated to further verify that the embedded PLC module can not only be used alone,but also can build a multi-node joint control system to complete the task of industrial control.