Oversized machines
December 1st 2004 Technology in the building management sector is developing at a fast pace with the increased integration of control systems and use of web based solutions.
However, until recently, the supervision of building management systems has required discrete management operations. Here, Stephen Hayes, of Hayes Control Systems, looks at how building automation technology is evolving to cater for the requirements of managing modern buildings efficiently
Traditionally each part of a building automation system has had its own controls and this has proved sufficient. However, higher demands are now being placed on the performance of today's buildings.
They need to be able to cope with constant modifications to the layout, security systems need to become more efficient, trends need to be analysed, data must be more accessible and integrated, energy management must be improved and maintenance regimes planned. The aim is for buildings to become more effective, yet attain lower running costs at the same time.
Let us now consider some of the various systems in common use in traditional building management systems.
Lighting systems include DALI (Digital Addressable Lighting Interface), DSI, Digital, Analog and LON. Most building functions, such as air handling, access control, window opening, brightness, even button control all now use control systems. These have to be supervised discretely, even when they are combined on a shared field network.
This use of various systems operating independently is a constraint. For instance, dedicated hardware by its nature is often too inflexible to cope with new demands. Specialist installers and pre-ordained circuits that are assumed before the client takes occupancy do not allow for flexibility, so upgrades and retrofitting can be difficult.
These serve to hold the building back and make the job of the building engineer or contractor all the more difficult.
21st Century buildings require much more. According to a market survey carried out by the Institut fur Energie und Gebaude in Germany in September 2003, a building automation system requires compatibility to other systems, high quality, optimised price:value ratio and open data exchange. In short, building automation systems have to be compatible with each other.
Modern buildings are like oversized machines. They have devices that turn on and off.They have motors.They have controls. They have sensors, switches, relays and transformers and many requirements similar to that of a machine. Future building automation must therefore combine and run all decentralised control requirements with centralised controllers and one, central PC based control system. This will save both time and money by eliminating the need for parallel wiring of many different systems. Essentially, every device and variable in the building automation system can be accessed by a single, central web based application using any standard web browser.
Web browsers provide many advantages because they cost little or nothing and there is no training required. The use of the web browser means accessibility is possible anywhere at any time, without the need for software loading.
Combining this with wireless Ethernet technology such as 802.11b provides the facilities manager with control and monitoring solutions at an extremely affordable price. They will be able to see alarms, graphical displays, trend plots and even, reports all in a standard PDA.Accessibility to data and key operating information will no longer be restricted to sitting at one work station in the building. Information is readily available when and where required.
Such open and intelligent control of building services is now coming into effect. This intelligent building solution is based on upon standard PC technology, standard communications via the Ethernet network in all of today's buildings, DALI (Digital Addressable Lighting Interface) and the Beckhoff TwinCAT software.
This system provides unrestricted benefits and flexibility to the end user because it is completely open. The use of office wide Ethernet network infrastructure reduces cabling, while the web based solution enables management of the system from any standard desktop machine connected to the network.
Intelligent control allows buildings to become much greener. Energy usage can be easily monitored and measured, and HVAC systems can be individually controlled and measured, leading to a reduction in energy usage.
Lighting can be controlled individually via DALI technology and lighting applications can be extensively scheduled.A Preset can be enabled for both lighting and temperature for different daily or seasonal conditions. Even emergency lighting testing can be automated.
Security can also be improved with a complete building automation system.
Security and access control can be monitored. Alarms, and Data Logs and times schedules for that matter, can all be configured and managed through a standard web browser. Enterprise management capabilities enable alarms, security and maintenance to be managed centrally. Fire alarm acknowledgement can also be monitored by the web server software along with representation of data from all connected systems.
Connectivity to many open standard communication protocols such as LonWorks,OPC,DALI and EIB is possible.
A truly integrated offering, connectivity to other building control systems, such as the BMS, is enabled. Open database formats even enable integration to other business systems. | 
