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

HVAC Control in the New Millenniumforms its function, which may be algorithms or methods, and sendsmessages to other objects as its outputs.Objects are event-driven, waiting for a change to start an action.They do not know anything about the objects that provide the inputs orthe objects that receive their outputs.They may be replicated to extend functionality and replaced toimprove performance or change behavior. Removal is simple when thefunctionality is no longer needed. All of this can be done without impacton the overall project function.Objects are tolerant since they do not care about the makeup orcomplexity of other objects. A control object could be a PLC, since thePLC can be encapsulated and treated as an object.Object based solutions can be deployed alongside existing traditionalsolutions and when it is desired to replace existing systems withnew ones, it can be done smoothly and effectively.Objects are trusting since they always assume that the downstreamand upstream objects will always do their tasks. Objects are widely distributablesince they do not require other objects to reside on the samecomputer platform and they do not mind if other objects are relocated.Objects behave the same if they function on their own or are a partof a complex control solution. They scale up to meet the demands of thesituation.Object-based solutions have been used to automate many plantsand process solutions in the oil and gas industries. In these, complex sequentialoperations were used to ensure consistency and completion. Theobject-based solutions that replaced them were easier to implement andmaintain and perform more effectively than the systems they replaced.Operating SystemsIn this information age, personal computers have become an everydaypart of life, both at home and at work. But, these computers areuseless unless you can easily access the information.Operating systems provide an interface between the user and thecomputer, allowing the user to access and control the computer resources.The operating system controls the access to the processor andinterfaces with the different system resources such as hard and floppydisks, CD-ROMs, printers and modems. The operating system acts like©2001 by The Fairmont Press, Inc. All rights reserved.