The next step up is building-/campus-based solutions, which are
typically centralized, meaning all devices communicate with a central server that authorized operators can access. This setup provides
a single control point for a building or campus, facilitates ongoing
lighting management, permits complex control-strategy programming, and can collect energy information and conduct monitoring for
maintenance and recommissioning. Offering the best opportunity for
energy savings and information, this option is the ultimate in lighting control, though it typically poses greater cost and complexity. For
that reason, current commercial building penetration is estimated at
2 percent, though it is expected to grow.
Centralized intelligent systems represent the ultimate in lighting
control, but they are sophisticated and require good design, installation and commissioning. Furthermore, manufacturers use distinct
approaches to differentiate their systems. Designers and installers
should familiarize themselves with the features and architecture of
the various systems to ensure smooth projects.
Since centralized intelligent control systems are more challenging
but have good growth potential, the remainder of this article focuses
Centralized intelligent systems
Centralized intelligent lighting control systems must be connected
within a topology. These systems may be wired, wired with wireless
accessory devices (“hybrid”), or completely wireless.
Various wired topologies are available. The most common is a bus
(basically a computer network). All control devices connect using
one pair of low-voltage wires, Ethernet or proprietary cabling.
For greater flexibility, some wired systems incorporate
wireless accessory devices (e.g., switches and sensors) that communicate with the system using one or more central gateways.
Alternatively, the system may be completely wireless
with the majority using a self-healing mesh or star topology.
In a self-healing mesh network, data flows through a network of devices along the most efficient path; if one device
fails, the data routes through a different path (self-healing).
In a star topology, signals from all wireless devices are
transmitted within range directly to and from one or more
gateways that form the network backbone.
The centralized intelligent lighting control system is designed in
accordance with a common protocol. The protocol may be open (e.g.,
DALI and ZigBee), allowing products from different manufacturers
to mix in the same network. On the other hand, it may be proprietary
to a manufacturer. For the control system to integrate with a building
automation system (BAS), the two systems must share the same native
protocol (such as BACnet); alternatively, one can use a gateway and/
or gateway-functional programming that can translate data crossing
between the systems.
Centralized intelligent lighting control systems are set up and operated using server-based software that is accessible from a workstation.
The programmer can create zones, discover devices, assign the devices