Lonworks Fieldbus Process Control And Remote Monitoring System

The fieldbus is now the hotspot of application in automation field. And the LonWorks, with its complete protocols, diversity of net topology structure and strong ability in network communication, excels in the fieldbus field. With the development of information in enterprises and intelligence in families, and with the use and rapid development of Internet technology, it's inevitable to develop control network and information network integrated technology by combining the control system with MIS tightly.This thesis introduces a process control system based on LonWorks fieldbus with remote monitoring ability. The system adopts three-level mode which comprises Internet, Intranet and Infranet.In this thesis, the system consists of three parts, the field control rank, the upper control and supervising rank, and the remote monitoring rank. It includes the LON general intelligent node, the upper control and supervising configuration platform, and the remote monitoring platform. The field control rank and the upper control and supervising rank adopt two-layer complete distributed structure. In addition, the remote monitoring rank takes mixture structure of C/S and B/S to develop their own advantages.Firstly, the thesis recounts the process of hardware designing and software development based on the LonWorks fieldbus control network. It introduces hardware designing and software programming of LON general intelligent nodes, the software developing of the VCSC, and the designing and realization of net communication protocol.Secondly, based on comparing the advantages and disadvantages of the C/S mode with that of the B/S mode, the thesis adopted the mixture structure of C/S and B/S to realize remote monitoring. It consists of two parts, LAN data transmission with C/S mode and remote data transmission with B/S mode. Then the thesis introduces main technologies of the two parts, such as Winsock, Web database, ASP, ActiveX, and so on.At present this system has been successfully applied to the process control system laboratory. Its use in real-timely control and monitoring the experiment equipments such as the pressure, the flux and the liquid locationshows good effect. In this thesis, an example of multi-node linkage control is presented to demonstrate the advantages of this system such as flexible structure, distributed control, friendly configuration interface, easy operation, reliability, and so on. It proves to be of practical value.