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S Components’ U.K. division headquarters is a purpose-built800,000 ft2 (74 000 m2) complex (equivalent in size to five football
fields) in central England. The site consists of administrative offices,calibration laboratories, call centers, and warehouses, the tallest ofwhich boasts the most level floor in Europe to prevent stacking ve-hicles from toppling at their full height extension. The main areas ofthe site are operational 24 hours a day, 365 days a year.
common language, and thus be con-nected onto a single facility-wide com-munication network.
A major benefit of this would be thereduction of electrical wiring necessarywhen monitoring and controlling equip-ment, such as boilers, chillers, genera-tors and equipment associated with otherbuilding services. Without usingBACnet, the site would have requiredmany “hard-wired” connections with theBAS controls to monitor faults and toprovide system interoperability. Instead,sensor readings, alarm conditions andoverride facilities could be broadcastthroughout the entire network, allowingthem to be accessed by users within asingle graphical BACnet supervisoryplatform. This would enable the companyto mix and match equipment and con-trols from various manufacturers on site,giving them complete freedom of choicefor future retrofit and expansion projects.
The company installed various controlsystems to help its plant and services de-partment engineers to run the site effi-ciently. However, using differentmanufacturers’ controllers meant the de-partment had to operate a different PC op-erator workstation (OWS) for each vendor.With the site expanding and more con-trols being fitted, a decision needed to bemade regarding which controls manufac-turer to standardize on in future projects.
Various manufacturers were consid-ered, and the facility engineers attendedtrade shows to research the latest tech-nologies. After discussions with severalsuppliers, the plant and services manage-ment agreed that all new plant equipmentand controls installed on the site mustbe native BACnet. The primary reasonfor this decision was that the BACnetopen protocol would enable variousequipment and controls to “speak” a
N o v e m b e r 2 0 0 3 B A C n e t ® To d a y | A S u p p l e m e n t t o A S H R A E J o u r n a l B15
In addition, the company required all new equipment installedon the site to provide more functionality than the limited con-trol and status monitoring capabilities of existing units, whichhad been “hard-wired” to the BAS controls. By using a BACnetsystem, operators were given greater control flexibility, whilereceiving more detailed information of in-ternal faults and measurements fromBACnet equipment. This has proved to beinvaluable to engineers for recognizingand reacting to problems more quickly, aswell as for planned maintenance.
Figure 1 shows a simplified representa-tion of how the network is laid out. Engi-neers monitor and control the site from acentral head-end graphics PC workstation.They are able to check for faults in themorning to prioritize their workload for the day. They also canlook for operating anomalies that may indicate a fault in themaking and, at the end of the day, ensure everything has beencleared and all services can run according to their programmedoperation.
Due to the immense size of the facility, three other operatorworkstations are located around the site that are set up to su-
pervise various alarms. This enables event and alarm notifica-tions to be routed to different stations depending on sourceand time of occurrence.
The BACnet system is set up to be simple to use, despite itshigher level of functionality. Operators can view equipment
status without the need for previouscomputer experience. This is achievedby displaying faults from variousequipment manufacturers on a singlescreen, with the ability to navigate to avisual representation, or mimic, of theassociated building system. This makesit simple for operators to readily accessstatus information across the entire site.
The various equipment and systemscontrolled and monitored are associ-
ated with the HVAC, life-safety, lighting and other electricalservices. The most recent additions include new chillers, manyfan coil units and variable-air-volume (VAV) boxes, as well asthree generators capable of powering the entire site in theevent of any power disruptions. All units are fitted with BACnetcontrollers. The communication of all main plant controllersuses a high-speed fiber-optic Ethernet LAN.
‘With the site
expanding and more
controls being fitted, a
decision needed to be
made regarding which
controls manufacturer
to standardize on in
future projects.’
BACnet helps facility staff to prioritize their workload for the day.
Warehouse complex in Corby, U.K.
B16 B A C n e t ® To d a y | A S u p p l e m e n t t o A S H R A E J o u r n a l N o v e m b e r 2 0 0 3
Primary HeadEnd PC
OWS PC OWS PC
Engineer’sLaptop
Ethernet Network
EIA-232 Link to Gateway Unit
Native BACnet Controller
Native BACnetController
BACnet Gateway
CommsLink to
GeneratorSets
Various native BACnet building controllers installed at keylocations within the facility are connected to the Ethernet fiberbackbone. Each controller supports a BACnet MS/TP subnet-work that connects to native BACnet field controllers for allother HVAC equipment, such as the air-handling units, fan coilunits and VAV boxes. For example, VAV boxes fitted with BACnetcontrollers serve the main office complex. These controllerscommunicate on a BACnet MS/TP subnetwork. The main plantand services PC workstation is used to monitor and control thisarea, allowing changes such as setpoint and time schedule ad-justments, to be performed as and when required by operators.
BACnet operator workstations also include fully animatedgraphics, allowing operators to view and adjust system func-tions such as time schedules, alarms and trend logs, as well asproviding a complete view of each area within the site. About150 control units are installed at RS, with new units continu-ously added as various areas undergo retrofit or expansion.
The BACnet control system has resulted in greater choice andflexibility for the plant and services department to select equip-ment and systems.
Carl Bate is project manager at Building Environment Con-trol in Newcastle-under-Lyme, U.K. Building EnvironmentalControl is an authorized system partner for Delta Controls.
Figure 1: Simplified diagram of BACnet network.
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