HVAC Control in the New Millennium.pdf - HVAC.Amickracing

Energy and Power Management, Distributed Control Trendstions. Some of these products are an outgrowth of supervisory controland data acquisition (SCADA) systems.Industrial NetworksIn modern factory and plant environments, any islands of automationin the past are steadily melting away with the connection of essentiallyeverything to nuclear networks.Today, there are three levels of networking:• enterprise networks up at the top,• control networks in the middle level, and• device level networks at the lowest level.The fieldbus standard may evolve to the practical emergence of severalparallel and perhaps overlapping standards. Each of these may be suitedto a particular industry and/or environment. Industrial extensions ofEthernet and TCP/IP will become the defacto standards for connectivityexternal to the system or machine.The future will see the proliferation of Ethernet at all levels. Itsperformance and cost will stamp out the need for alternatives. Low costwill be fed by acceptance and high volume in most application areas.Wireless ConnectionsWorldwide connectivity is moving very quickly to link everyoneand everything to the Internet. This will take place not only throughhigh-speed DSL and cable modems, but also through third-generationwireless systems. The analog technology of first-generation cell phonesslowed the adoption of advanced digital wireless technologies in theUnited States. Because of the entrenched infrastructure of the analogtelephone system the initial growth was slow compared to Europe,which quickly jumped directly to second-generation wireless digitaltelephones. In the near future, advances in low cost microcircuits willallow broadband wireless connections at speeds exceeding twisted pairlandlines and nearing that of cable connections.This will have a major impact on control systems. Connecting con-©2001 by The Fairmont Press, Inc. All rights reserved.