48 MAY/JUNE 2017 LEDsmagazine.com
In just the last five years, LEDs have com- pletely transformed the lighting land- scape. Originally embraced as an ener-gy-saving option for lighting retrofits and
code compliance, lighting professionals
and their customers often had to compromise — efficiency versus ambience. Not anymore. LED lighting offers a wide variety of
advantages including excellent color rendering and superb dimming capability. Tunable
white is the current hot topic, and digital
control is essential for making the most of
white tuning potential.
White tuning research is still relatively
new, but the evidence increasingly points
to a wide variety of human-centric benefits,
and potentially even health benefits, that
can be realized through control of fixture
color temperature ( http://bit.ly/2cL4Fnn).
Specific, physiological benefits are still
unclear, but there is no question about the
aesthetic value and flexibility white tuning
provides. Lighting designers and specifiers
are looking for a simple way to use this new
technology to better meet their customers’
needs. When considering your options, digital controls far surpass the performance of
analog control, and will often end up being
both simpler to design and even less expensive than 0–10V.
Digital controls deliver consistency by
ensuring that each fixture has the same color
temperature Other benefits include a reduction in the risk of installation issues while
improving reliability; precise control of color
temperature; and scalability for basic tunable-white or full color-gamut control. Let’s
walk through these benefits in more detail.
When light levels are just being adjusted
up and down, it doesn’t necessarily matter if the 0–10V control signal isn’t precisely matched across fixtures. Particularly
at high end, humans are not terribly sensitive to relative differences in light intensity. However, when control of intensity and
color temperature is combined, precision
is essential. Humans are more sensitive to
changes in color than they are to changes in
intensity. The typical margin-of-error in a
0–10V system will cause fixtures
on the same control to be a different color. So the consistency delivered by a precise tunable system
eliminates this issue (http://bit.
Even though 0–10V is the most
common control type, it’s a rare
project that comes to fruition
without at least one wiring issue.
Now, add a second set of control wires for
each fixture, and the opportunity for error
goes up exponentially. These errors may
not always be detected by a basic function
check. If the intensity and color temperature controls are crossed, a casual function
check can easily miss this behavior, and the
result is often a costly callback to the electrician. In addition to simpler and more robust
wiring, digital controls are also immune to
noise — even if your control wires are near
an electrically noisy area, you will not see
undesired behavior in the lighting. This has
always been a benefit of digital control, but
it’s even more important with tunable white
due to the increased sensitivity to differences in color.
The ability to set a precise and consistent
color temperature at the fixture with digital
controls is a huge win compared to analog
control. It’s important to consider, however,
that when it comes to precise color temperature throughout the space, even digital controls alone may not be sufficient. For comprehensive control of color in the space, the
ambient lighting from the windows must
be accounted for. Combining digital color
temperature control with a precision shading system enables even the most
particular occupants to create the
environment they need.
Finally, using a digital protocol provides the ability to deliver
multiple dimensions of flexibility — in other words, digital control enables a range of solutions
from simple, two-color fixtures
to high-performance, precision
solutions with four or more colors employed
to create the desired atmosphere. Such performance with 0–10V controls requires an
additional control wire for each dimension
of flexibility, which is not at all practical.
As the lighting design community continues to more effectively leverage the
power of tunable lighting, lighting designers, architects, and engineers will demand
simple, reliable solutions that scale with
their needs. Digital controls are the only
way to guarantee desired results. The more
we learn about how lighting affects the performance of both buildings and the people
in them, the more diligent attention needs
to be paid to the control systems we select
for each project.
Tunable white lighting:
It must be digital
Forward-thinking control system providers have the opportunity to drive progress, push
the technology envelope, and set the standard for digital controls that help create
dynamic, personalized environments in any space, explains Lutron’s CRAIG CASE Y.