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

Artificial Intelligence, Fuzzy Logic and Controllevel of safety for automatic control and monitoring of start-up, operation,and shutdown of the boiler.In Melbourne, Australia, a new BMS was installed at the NewportPower Station. The strategy was to upgrade the 1980s stand-alone combustioncontrols using a new distributed control system (DCS). The tightintegration planned for the two systems was simplified by the flexibilityin the BMS design, which also can operate independently of the DCS.There is a total of 60 burner elements, with each element requiringindividual control and monitoring with a high level of requirementsrelated to safety. A QUADLOG safety system from Moore Process AutomationSolutions was used. It has a one-out-of-two-diagnostic (1oo2D)redundant architecture. In the 1oo2D redundant architecture, there aretwo processors, each with its own backplane and infrastructure.The PC-based programming software runs on Windows NT andprovides an intuitive, user-friendly graphical configuration. There is achoice of several programming languages: ladder logic, function blocks,sequential charts, or structured text. The graphical configuration capabilitysaves hours when making on-line changes. The system is fullyself-documenting and the high availability of the system results inhigher plant availability.If the on-line diagnostics detect a failure in one system, the othersystem automatically assumes control and the safety system remainsavailable. The control and I/O modules fit into slots with 10 to a rack.There are four racks assigned to purge and fuel safety, and 8 assigned tothe burners and igniters. The racks are connected to a LAN, along witha workstation located near the racks and 2 workstations located in thecontrol room.Each of the 20 gas burners, 20 oil burners, and 20 igniters has itsown flame detection system, valves, limit switches, air dampers, andother equipment. The overall safety system has four burner subsystems:• igniter fuel trip,• gas fuel trip,• oil fuel trip, and• master fuel trip.All failure modes are predetermined in the hardware and firmware to afail-safe condition. Alarms are used to identify them.The application software for sequencing operations allows a single©2001 by The Fairmont Press, Inc. All rights reserved.