Cover 1_rto4 - Illuminating Engineering Society
Cover 1_rto4 - Illuminating Engineering Society
Cover 1_rto4 - Illuminating Engineering Society
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Willard L.<br />
Warren,<br />
PE, LC,<br />
FIESNA<br />
Asophisticated new lighting<br />
control system that uses digital,<br />
rather than analog, signals<br />
to control the light output of a<br />
ESSAY<br />
BY INVITATION<br />
which particular lamps and ballasts<br />
are in need of replacement.<br />
The DALI system can be programmed<br />
to turn units on or off, or<br />
dimmed from 1-100 percent light<br />
output, by means of a simple low<br />
voltage control wire that loops<br />
through the building to every fixture.<br />
Further, when DALI is used in<br />
conjunction with a building management<br />
system, every lamp and<br />
ballast can be addressed to determine<br />
if the lamp or ballast is in<br />
working order. This status report<br />
can be gathered, either on-site, or<br />
at the central office of a maintenance<br />
contractor, to determine<br />
how many replacement lamps and<br />
ballasts are required, what kind<br />
It can<br />
feed back<br />
information<br />
on which<br />
particular<br />
lamps and<br />
ballasts are in<br />
need of<br />
replacement.<br />
Figure 1 — User interface<br />
Figure 2 — DALI software<br />
digital electronic ballast was recently<br />
introduced into this country<br />
The new digital electronic ballast<br />
and its control will replace the analog<br />
electronic ballast as the international<br />
standard in a few years<br />
because of its incredible versatility.<br />
The acronym for the new control<br />
protocol is “DALI,” which stands for<br />
“Digital Addressable Lighting Interface.”<br />
The beauty of DALI is that it<br />
allows the user to address every<br />
individual digital ballast, and program<br />
its lamp’s light output. And,<br />
because DALI is a two-way system,<br />
it can feed back information on<br />
they are, and where they are located.<br />
This saves time and money<br />
when servicing multiple sites in<br />
the same geographical area, like<br />
department stores, chain stores<br />
and supermarkets.<br />
The DALI system also allows digital<br />
ballasts to be controlled wherever<br />
they are in the ceiling, so if<br />
changes are made in the arrangement<br />
of departments on a floor,<br />
the lighting luminaires do not have<br />
to be re-wired, just re-addressed.<br />
Because the DALI system controls<br />
every individual ballast, it allows<br />
the user to assign every fixture to<br />
any one of 16 different groupings<br />
of luminaires in the space, and create<br />
multiple operating modes or<br />
scenes. Lighting levels can also be<br />
adjusted to respond to conditions<br />
like energy cutbacks, daylight harvesting,<br />
occupancy status, or the<br />
system can be used to turn any<br />
part of a large office into a conference<br />
area, with the ability to dim<br />
any fixtures needed to facilitate<br />
audio/visual presentations.<br />
The DALI system can be<br />
accessed either by a PC or a Palm<br />
OS device. Figure 1, the user-friendly<br />
PC screen, shows how easy it is<br />
to set the output of the ballast and<br />
assign it to one of 16 fixture groups.<br />
In the third step of the DALI program,<br />
the user selects the fade<br />
time and fade rate of each ballast.<br />
Figure 2 shows the control plan of<br />
three groups of luminaires, how<br />
they will be dimmed, and at what<br />
time. The user simply draws the<br />
fade and time curve with a PC<br />
mouse, and each group of ballasts<br />
creates the desired scene, as programmed.<br />
The PCs or Palm controllers<br />
can be located at several<br />
locations on the floor and changed<br />
at any time.<br />
Many American and European<br />
manufacturers have already signed<br />
on to provide hardware for this new<br />
16 LD+A/May 2001 www.iesna.org