Using Zigbee to build a web-based DCS system

This paper presents the design and implementation of a web based Distributed Control System DCS built on wireless communication protocols IEEE 802.15.4, Zigbee and Digimesh. The development of decentralized (distributed) input-output Systems used for the process control, data acquisition and monitoring could be executed by dividing the overall system into many subsystems, each carries only the code necessary for a specific set of activities in contrast to a centralized control system that requires complex programming needed to govern the entire system. The monitoring and process control unit for each subsystem is geographically distributed in the controlled plant, each subsystem node is based on the wireless Xbee modules Series I or Series II, which are capable to be configured to work in a network under some different topologies like star, cluster tree and mesh. With these module implementations of the Zigbee Wireless Networks with geographic coverage increasing rang are possible. Xbee module is a low cost and powerful tool for implementation of distributed control systems. Because the basic standalone XBee radio does not allow access to any kind of logic, the incorporation of external microcontroller to each subsystem node will be necessary to allow some form of local logic that requires knowledge of the C-like language. i.e up till now Xbee Module by itself is not intelligent. The Application Software for operator interface will be networked over the Internet to accomplish remote monitoring and controlling over the plant Ethernet using Dot Net programming technology (ASP.Net and Visual C-sharp) and the interface will be displayed as a secured HTML page in a website. The above idea will be verified via a representative example using the technologies presented in this paper.