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necessary to ensure that the signal path will not be impeded.
RF can also interfere with other unrelated systems. We have
all heard the feedback and interference that comes through on
two-way radio systems. In a wireless building network, this
would be a “show stopper.”
Infrared signaling (IR) technology is limited primarily by
line of sight. We know that to operate something as simple as
a television remote control, we must point it directly at the
set. If not, nothing happens. In a situation where a dedicated
air conditioning unit is located in a space along with a wireless
thermostat, IR technology may be acceptable. In a multiple
room scenario, IR is not an option.
Virtually all wireless devices, regardless of how they are
networked, will require battery power. The reliability and
capability of the batteries become a key success factor in the
effective operation of the system. How much data can be
communicated How far must the data travel How often are
the communications cycled How will low battery power affect
the building controls What is the alarming capability of the
batteries Without a clear understanding of these issues,
wireless building networks can be a risky proposition.
WIRELESS INFRASTRUCTURE
The current state of wireless building networks is far from
optimum, although growth is undeniable. The use of twoway
radios, cellular telephones, pagers, PDAs and voice-over
Internet protocol (VOIP) systems has exploded. Many of these
systems, however, have been installed in a piecemeal fashion,
without a systems engineering approach. Communications
quality is often poor. This is largely due to the lack of a
comprehensive controls system strategy and the resulting
interference from sources outside the facility. System security
is also questionable. If unintended signal interference from the
outside is possible, then it’s also feasible that somebody could
knowingly access the system without proper authorization.
More often than not, poor perceptions are the result of a lack
of discipline in deployment of wireless networks, not in the
technology itself.
When wireless building networks are conceived using an
engineered distribution system approach, the aforementioned
issues tend to disappear. Imagine thousands of control devices
working together to improve the total environment. These
systems impose discipline in their application and therefore
enable quality, reliable performance and efficiency. They
typically require less maintenance, as there are fewer
components to wear out. They offer freedom of movement
that will “unchain” key staff members from their desks. They
offer a facility-based shared infrastructure that would support
approved wireless devices and applications and contain the
network so that outside interference is negated. They are
typically created using Ethernet technology to provide a wider
frequency range, supporting both current and emerging wireless
applications. They allow for fewer time-consuming, costly
relocations. Lastly, they allow building management interface
to areas that are unreachable with traditional conduit and
wire systems.
APPLICATIONS
With the proper infrastructure, the possibilities are limitless.
Here are a few applications that would provide tangible benefits
to whole industries.
Facility management
Facility engineers and managers operate on the go. When they
are able to get real-time systems performance data and adjust
operating parameters through a networked PDA (or other
device), they are able to quickly respond to issues and operate
more efficiently. They would also be able to receive maintenance
requests from building occupants through a
Web site and immediately address the problems, without
having to check in with a central office or spend time on
needless paperwork.
Building security
Building security systems are much more effective when they
are adaptable to ever-changing conditions. Cameras
and monitors interfaced through a wireless network can be
relocated as necessary to focus on critical areas. Hardware
and other valuable equipment can be tracked with networked
equipment tags—even people can be monitored if need be.
Research and development
Laboratory efficiency can be dramatically improved with
wireless technology. Researchers are able to monitor ongoing
research activities remotely and communicate to graduate
assistants and other support staff in real time. New processes
and equipment can be integrated into existing operations more
quickly and at less cost. Environmental health and safety
(for example, space ventilation and pressurization) can be
continuously monitored and action taken immediately if
something falls out of calibration.
Healthcare
Hospitals have been using wireless technology for years (for
example, doctors carrying pagers). We are now seeing a much
broader application. With wireless networks, doctors and
nurses can monitor a patient’s vital signs remotely; order
prescriptions electronically; and monitor the location of
patients and mobile life-sustaining equipment. Imagine being
a patient and having the attributes (temperature, relative
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