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

Computer Networks and Securityconnected. Now, in addition to shutting down lights, the occupancysensors can send a signal to the HVAC system to adjust heating or coolinglevels as well.The LonWorks system was designed by Echelon to use a proprietaryintegrated circuit called the neuron chip. A special communicationsprotocol is used with these chips which are manufactured by severalcompanies, including Motorola and Toshiba. LonWorks allows aseamless connection between systems that are designed using the sameparameters.The neuron chip is designed to communicate with field variables,run process control loops and communicate with other neuron chips.The chip can be used for monitoring and control at different levels in thesystem. Some manufacturers even use the neuron chip in the main controllerof their EMCS system. While these systems use LonWorks, theyare not true LonWorks systems.Open systems like LonWorks also allow customization. Open,interoperable products and architectures allow the overall infrastructureand system to fit the needs of the end-user and the facilities manager.Once the infrastructure is put in the building owner has a fullyintegrated, intelligent unit. Applications can be added as needs changeand grow. As new sensors and applications are developed, you can justchange components.The hardware platform is based on the Neuron chipset, whichprovides I/O processing and data communications. Software is based onthe LonTalk communication protocol, which provides a set of standardizedmessages and a development tool for applications.The original implementation of LonWorks required a licensingagreement from Echelon. Since that time, Echelon has allowed users toport LonTalk protocol to a number of different hardware platforms thatprovide increased performance over the 8-bit Neuron processor.BACnet and LonMarkManufacturers are delivering products that are compatible withboth BACnet or LonMark. While BACnet and LonMark have their ownbenefits, manufacturers are finding them to be complementary. Thecomplementary nature of the two standards allows different building controlsystems to communicate with each other and exchange information.©2001 by The Fairmont Press, Inc. All rights reserved.