wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

Building and Home Automation 26-7
TABLE 26.1
Domains of Building Services
Domain
Climate control
Visual comfort
Safety
Security
Transportation
One-way audio
Energy management
Supply and disposal
Communication and information exchange
Miscellaneous special domains
HVAC, humidity, air quality
Typical Building Services
Artificial lighting, daylighting (motorized blinds/shutters), constant
light control
Fire alarm, gas alarm, water leak detection, emergency sound system,
emergency lighting, closed-circuit television (CCTV)
Intrusion alarm, access control, CCTV, audio surveillance
Elevators, escalators, conveyor belts
Public address/audio distribution and sound reinforcement systems
Peak avoidance
Power distribution, waste management, freshwater/domestic hot water,
wastewater
IT networks, private branch exchange (PBX), intercom, shared WAN
access, wireless access (WLAN)
Clock systems, flextime systems, presentation equipment (e.g., video
walls), medical gas, pneumatic structure support systems (for airhouses)
Moreover, different building services have been embraced by BAS. A summary of different building
service domains is given in Table 26.1.
Climate control is still the most important domain, including the original HVAC applications. The
underlying physical process can be measured and influenced using well-known devices. Heating systems,
for example, include variable air volume systems to fan-coil units. The timing constants of the
process are long and thus make the process simple to control using network-based control systems
like BACnet, KNX, and LonWorks. More novel systems also include control loops for air quality and
humidity.
Another well-established building service domain is visual comfort. This domain comprises lighting
applications (e.g., daylight), constant light controllers, and scene selections for special rooms such as
meeting rooms or executive offices. Lighting applications have much more stringent requirements on
response time than HVAC. Typical switch commands must be transmitted faster than 400.ms to give the
user an instant feedback. Also constant light control requires faster adaption to environment conditions
than temperature control, as the human eye responds much faster to changes. Typical installations for
lighting rely on KNX or LonWorks systems. The light switches, touch panel units, presence detectors,
and luminaires are interconnected over a communication system. The constant light controller units
often also have direct I/O ports to light switches. Modern luminaires frequently use the DALI standard
for communication, which is especially easy to install, as the same cabling is used for the communication
path as for the power cabling. Two installation scenarios are in place: room-based installations are
based on KNX or LonWorks, and floor-based cabling is used for DALI luminaires. The DALI light controllers
are often installed per floor or floor segment spanning multiple rooms and provide an interface
to the BACnet-, KNX-, or LonWorks-based infrastructure installed in the rooms to realize constant
light control. Other components in visual comfort comprise shading and sunblinds, which control the
admission of daylight into a room.
Two important domains that are still often neglected are security [26] and safety [30]. Security refers
to protecting the building premises from unauthorized access (access control) and intrusion detection.
Systems in this area use proprietary protocols as well as open technologies, such as BACnet (access door
objects) and LonWorks (authorized services). Typical devices are window and door contacts, CCTV
devices, and presence detectors. Safety applications refer to life safety and include monitoring and alarm
management of numerous building parameters. If a parameter exceeds its normal range, alarms are generated
and dissipated through the system. This is a typical function of building controllers. Systems such
as BACnet provide standardized objects for life safety and life safety zones. Fire alarm and emergency
© 2011 by Taylor and Francis Group, LLC