The Pros and Cons of Wireless Lighting Control

Turning off lights when they are not needed isWhile mesh networks provide many benefits for
one of the best ways to save energy. This islighting control, and removing the wires provides
especially true in commercial buildings, whereeven more including increased flexibility and
lighting can account for up to 40% of thereduced installation costs. But no single solution is
building's total energy cost.perfect for everyone. Below is a summary of
With wireless lighting control, you don't need toboth the pros and cons of wireless mesh lighting
rely on employees to turn lights on and off.control:
Instead, you can take advantage of scheduling,- Cost: Installation costs are greatly reduced
timers, occupancy sensors and photosensors towithout the need to run control wires from each
deliver the optimal illumination level in all situationsdevice back to the central controller. However,
while minimizing wasted energy.wireless sensors and controls are sometimes
Many traditional building and lighting controlmore expensive than their wired counterparts, so
systems are fully wired, with all lights, sensors andsome of the money you save on wiring may go
switches hard-wired to a central controller orback into purchasing the wireless devices.
gateway.- Security: Both wired and wireless solutions
Newer lighting systems take advantage ofprovide effective security. Most wireless lighting
wireless mesh networking, which allows the lights,technologies use 128-bit Advanced Encryption
sensors, switches and the central controller toStandard (AES) security for communications. This
communicate with each other without the needsecurity is robust enough that, in June 2003, the
for wires. Removing the wires provides moreUS Government announced that AES may be
flexibility in terms of where switches and sensorsused to protect classified information.
can be placed, and makes it more affordable to- Scalability: Wireless mesh solutions support more
include additional sensors in the network.devices over greater distances than wired ones,
Wireless mesh also supports more flexible andwhich makes wireless ideal for multi-office and
easier control of larger systems with moremulti-floor installations. The nature of mesh
devices. It allows you to run your lighting controlnetworks means that simply adding new devices
solution as a single system that covers an entirecan extend the communication coverage of the
building (or multiple buildings), as well as room bynetwork. And the wireless nature of the controls
room (or floor by floor) deployments. Thisallows you to place them in areas that were
provides a system-wide view of operations,previously difficult or costly to access.
current power usage, savings, and more.- Reliability: Both wired and wireless networks use
So how does a wireless mesh network work?mature technologies that offer great robustness
It consists of a mesh of interconnected devicesand reliability. There is the potential of radio
(such as luminaires, switches, and controllers). Eachinterference and data loss with some wireless
device contains a small radio transmitter that ittechnologies that share the same radio frequency
uses for communication. The transmitters can be(such as Wi-Fi® and ZigBee®). Fortunately,
built in to the device or can be fitted externally.this problem is easily avoided for your lighting
In a wireless mesh network, each device issolution by selecting channels within the radio
typically connected through at least twofrequency that are not commonly used by other
pathways, and can relay messages for itswireless devices. You can further protect yourself
neighbors.by selecting a wireless mesh technology like
Data is passed through the network from deviceZigBee, which can automatically switch to a new
to device using the most reliable communicationchannel if it detects interference on the current
links and most efficient path until the destination ischannel.
reached. Two-way communication also helps to- Flexibility: This is one of the biggest benefits of
increase reliability, by allowing devices towireless. Devices can be installed where they will
acknowledge receipt of data and to requireprovide maximum benefit instead of where it is
retransmission of data not received.easiest to run wires. Devices are also grouped
The mesh network is self-healing, in that if anyinto "zones" using addressing and software rather
disruption occurs within the network (such as athan hard wiring, which allows changes to be
device failing or being removed), data ismade at any time through simple software
automatically re-routed. The built-in redundancy ofreconfiguration (no costly or disruptive rewiring
having multiple pathways available helps to makerequired).
the mesh network both robust and reliable.- Complexity: Wireless allows you to avoid the
Mesh networks are also highly scalable, in that youcomplexity of connecting wires from hundreds (or
can extend the network simply by adding morethousands) of devices back to a controller, but
devices. The network's self-configuring capabilitiesthat comes at a price. It can be more difficult to
identify when a device is added: working out whatlocate a device when you don't have wires to
type of device it is, where its neighbors are, andfollow. The good news is that tools are available
what the best path is through the network. Weakto help you locate and identify devices during
signals and dead zones can also be eliminatedinstallation and commissioning, and for the ongoing
simply by adding more devices to the network.operation, monitoring and maintenance of the
Pros and conssystem.