Study And Implement Of The Remote Monitor For Electric Network With Embedded Web Server

The real-time remote monitor to the electric network is an important measure to ensure its normal and reliable running. With the constant development of embedded technology and network technology, the monitor method by connecting embedded monitor device to the Internet gradually takes the place of the traditional method.Based on B/S mode, the paper puts forward a new method to realize the remote monitor to the electric network by applying ARM7 micro-processor to build the embedded web server. It has the advantage of flexible information and out-of-town browse.In the hardware design, the system applied micro-processor chip S3C44B0X with ARM7 core as the processor of the embedded web server. In order to realize the Internet connecting, the system also extended the network circuit based on the ethernet control chip RTL8019AS. In order to realize real-time and exact monitor, the system applied the synchronous A.C. sampling instead of the traditional D.C sampling to design the data-collection circuit of the electric network, which made the sampling data precise and reliable.In the aspect of software design, to meet the needs of complicated monitor tasks, the system adopted the embedded real-time operation system kernelμC/OS-Ⅱto carry out effective task-schedule and task-management to the system, and based on which, the system ported a light weight TCP/IP stack Lwip. In addition, the embedded file system was developed so as to build the software foundation of the system.Based on the software foundation, the system further developed the application software of the remote monitor system. By clipping the standard HTTP protocol as well as studying and implementing the embedded gateway interface (EGI), the system realized the design of the embedded web server so that the remote monitor could real-time monitor the running situation of the electric network with the browser. At the same time, in order to provide the warning message when running faults of the electrical network happened, the system also designed the email warning program based on SMTP protocol.Finally, the remote system based on C/S mode was also implemented due to the fact that the C/S mode has the advantage of good interaction and high translation speed, which can make up the shortage of the B/S mode. On C/S mode, the system improved the reliability of the UDP transmission by designing the resending mechanism of the UDP package, and developed the software of the client which was acted by the micro-processor S3C44B0X, at the same time, the system also developed the software of the server which was acted by the PC so that the monitor center can interact with the monitor terminal flexibly.The experiments results show that the system has the advantage of high stability and real time performance whether on B/S mode or on C/S mode. At the same time, the system is powerful because it has the advantage of both modes since it can alter between the two modes according to the needs of different circumstances.