Research On The Application Of Embedded Server In Monitoring PLC Device

With the development of embedded systems and the spread of internet, more and more embedded systems will include network. So the embedded systems can access the internet and own the function of network server, which can make users to monitor and management the systems at any time and at any place. At the same time, the network server provide users much rich and intuitionist data forms to improve the human machine interface(HMI).The thesis base on the project, the remote supervisory control system of embedded sever based on internet, is proposed under such background.The embedded server that the thesis research is used to supervisory control the PLC device on remote industrial field. The client use HMI developed by our laboratory to monitor the PLC device on the remote industrial field by embedded server. This embedded server can communicate with PLC device on the industrial field, read and write the internal resource of PLC that connected with it. It realizes a server based on Linux Socket. Many clients can browse the server but only supervisor can control the server. It also realizes the communication between PLC and Internet client which makes client can browse PLC and control PLC.The thesis firstly introduced the hardware and software of the embedded server, which is the base of the project. As the object of the embedded server supervisory control is the PLC and its network on the industrial field, the thesis also introduced the structure of PLC network, discussed the way of communication and the structure links in detail between the embedded server and PLC network. Then, we analyze and abstract the Mitsubishi PLC and Siemens PLC communication protocol in the thesis, established the communication protocol between embedded server and PLC network. The protocol is comprehensive and easily to be used between embedded server and most types of PLC communications. We illuminated the functions of configuration files, according to it's, the embedded server could achieve the user's requirements step by step. To study the capability of real-time communications between embedded server and PLC, we analyzed communication time series between embedded server and Mitsubishi FX2N series PLC, This is a good preparation for program. We also made brief description of communication procedures, provides programming problems which should be paid attention to, and list the procedures flowchart. Finally, we made a summarization of this thesis.Now, the embedded server was checked and accepted by client. Practice has shown that the contents and methods were introduced in the thesis have certain reference value.