Research On Embedded Ethernet Web Technology Of Process-Oriented Monitoring And Control

With the development of Ethernet as the most popular LAN, at present, it is applied to industrial control fields with embedded Internet together. This is a new trend as to monitoring and control system. Embedded Internet technology has changed previous structure of monitoring and control system. At the same time, it has satisfied the needs of expansibility, distribution as well as real - time performance of mordern monitoring and control system. There is an extensive prospect to research on the technology.The article focuses on two kinds of pivotal technology. One is concerned with embedded equipment access to Internet, the other is concerned with constructing Ethernet distribution monitoring and control system based on LAN. Firstly, it analyzes and summarizes existing industrial monitoring and control system, then comes to a general scheme design and Topology structure of embedded Web Server monitoring and control system based on Ethernet monitoring and control gateway. Secondly, it analyzes deeply TCP/IP Protocol Stack Nut/Net in Nut/OS operating system, simplizes and compresses reasonably the protocol stack and constructs three function modules, which include the setting parameter module of Web Server, the RS232 communication module and the switch and simulation quantities monitoring module of serial interface equipment, to support Web Server with Socket mechanism on the basis of applied-layer HTTP protocol and CGI technology.With a communication controller embedded in NC, a local monitoring and control system can be constructed in the workplace. And with gathering switch and simulation quanties when NC is processing, Web Server can monitor the situation of NC to control the equipment. In the scheme, the communication controller is the Ethernet monitoring gateway concerned. The hardware is made up of 8 bits SCM and RTL8019AS, the software adopts free code of TCP/IP protocal stack in real-time operating system.The article has explained in detail the hardware principle and the software mechanism in designed scheme, solved the problem how to construct LAN with NC in the workplace, and made helpful exploration to apply widely embedded Ethernet technology to monitoring and control fields.