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

HVAC Control in the New Millenniumtrol components conventional wire systems beyond the confines of atypical system enclosure is still a major task in many typical HVACapplications.Future controls will be accessible through portable wireless computerscarried by individual maintenance people, much as cell phonesare carried today. These portable wireless PDAs (personal digital assistants)will be connected via the Web to everything needed to read thelocal objects. These objects will include the specifications for each controlcomponent as well as maintenance, troubleshooting and repairdocumentation.Third-generation wireless connectivity will include the new localarea network technology called Bluetooth that allows I/O data transfersat 1 megabyte per second within a 10-meter radius.One inhibition to wireless operation is the fear of interference andtampering. This can be eliminated through modern encryption techniques,which are already being used in most banking, stock market andother high-value applications. The adoption of these security methods inindustrial automation should be relatively straightforward and completethe cycle of integration.DiagnosticsIntelligence allows diagnostics which can conduct not only in postfailure, but it can also be predictive and advisory in nature while providingmaintenance instructions.It is extremely useful to know that a failure may occur in the nearfuture. If a valve is sticking, it might be allowed to continue to operatewith some precautions. If the valve exhibits a particular symptom, thenimmediate maintenance may be needed.Predictive diagnostics allows components to be repaired or replacedduring off-season downtimes, before a problematic failure occursduring HVAC operation.This type of intelligence may reside not only in central computers,but also in an increasing number of controllers, actuators and displays.The intelligence aspect could become a part of essentially every productin the control system. Some types of failures are best diagnosed usingmethods that involve failure simulation and pattern recognition throughthe responses of intelligent I/O points in a complex adaptive system.©2001 by The Fairmont Press, Inc. All rights reserved.