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

Advanced HVAC Control, Information Technology and Open Systemsalarm condition and implement a corrective action.Future intelligent alarm management solutions may apply expertsystems. These systems provide a framework for diagnosing processdisruptions, generating more precise information and implementingcorrective actions.Expert Systems ReasoningExpert systems are applications of artificial intelligence (AI) thatapply inference engine and fuzzy-logic technologies to reason in realtime about events that occur in dynamic processes. The inference enginereasons from rules defined in a knowledge base that is derived fromexpert specific knowledge.Real-time expert systems can be divided into two basic categories:advisory and supervisory control. In advisory applications, the expertsystem reasons about changes in data, makes decisions based on eventsand presents conclusions and rationale to the operator.The expert system that acts as a supervisor; it has the ability toprovide information about control occurrences and impending problems.In some more robust supervisory control applications, the expertsystem will proactively adjust setpoints and switch discrete equipmenton or off to resolve problems, optimize control and attain other objectivesas defined in the knowledge base.Alarm management expert systems can be integrated with theoperator interface (OI) to supervise the control and provide on-lineadvisory or supervisory control functions. The expert system reasonsabout alarm points defined in a database according to tagged values,dynamic changes in a group of tagged values, or the state of otheralarms in the database.The use of meta alarms, which are alarms that reason about thestate of other alarms, allows a higher level of logic that captures thedynamic changes occurring in the environment.Conventional Alarm SystemsConventional alarm systems are typically advisory in nature. Theyare tag-centric. They provide discrete alarms based on an absolute limit©2001 by The Fairmont Press, Inc. All rights reserved.