Simply put, RGB stands for the three different types of LEDs within a color changing fixture; Red, Green and Blue.  RGB fixtures use the additive color system to combine emitted lights in order to create the sensation of a range of colors.  The additive reproduction process uses red, green and blue light to produce other colors.  Combining one of these additive primary colors with another in equal amounts produces the additive secondary colors cyan, magenta and yellow.  Combining all three primary clusters of LEDs at full intensity produces unbalanced RGB white.  The whole process of varying intensities is done through the DMX512 protocol.

Adopted from the entertainment lighting community, DMX512 is an industry standard communication protocol composed of 512 channels (1 universe), but multiple universes are possible when using more than 512 channels.  illumivision fixtures use three channels for the independent control of the red, blue and green intensities. The result means 170 illumivision fixtures can operate within a DMX512 universe.

After 10-15 years of normal usage, LEDs dim and will eventually require replacement.  Each fixture unit comes pre-assembled with LEDs bonded to the circuit board enclosed in a factory sealed unit.  As such, LED replacement requires an authorized technician.  illumivision does not authorize opening the fixture or the replacement of LEDs since the components are highly sensitive electronic technology.

LEDs are semiconductor devices with a much higher Mean Time Between Failure (MTBF) than conventional light sources (incandescent and halogen light).  As they do not rely on a filament to produce light, LEDs will not fail immediately, but often show a decrease in output over time (lumen depreciation).  Industry standards suggest that a fixture has failed when it reached 50% its original output. Despite this lumen depreciation, LEDs remain a more viable and longer lasting source of lighting output compared to conventional light sources. 

LED lumen depreciation is the result of environmental conditions including humidity, ventilation, and temperature.  Other reasons for lumen depreciation include means of control, thermal management, and other electrical design factors.  Low temperatures and precise effects have an advantageous outcome on lumen depreciation.  Overall, system lifetime varies based amount of use and the environment to which the product is exposed.  Ideally, according to manufacturer research, LED lifetimes span 80,000-100,000 hours.

Dimming LED fixtures depends on the design of the product.  Since LED’s are current driven devices, it is not advisable to lower the voltage in order to dim a fixture.  Pulse Width Modulation (PWM) or DMX dimming is most commonly used.  Although not technically stated in literature, dimming does not lower the lamp life of the fixture and can often increase it.

Since LED sources are solid state devices, they are most commonly powered by DC voltage.  In addition, the color changing features of some fixtures require a data line connected from a central controller. 

Common fixture voltages are 12 and 24 VDC.  Providing this voltage requires a power supply or driver.  Due to the low power draw, one power supply may operate multiple fixtures.  Consolidating many fixtures on one power supply reduces the size of the fixture, the cost of the unit, the number of problematic components onboard the fixture, and the heat build up in the fixture.

LED fixture test methods do not provide an accurate lumen output rating.  It is

acceptable to use lumens on their own when comparing LED fixtures types but not LED to conventional lamp sources.

Due to the nature of the source, LED will show up with a much lower rating when considering it may accomplish the same footcandle levels at a specific point on the illuminated surface.

Therefore, a photometric evaluation should be conducted when determining if an LED fixture is the right choice for a project.  In addition, a mockup of the application is a valuable evaluation tool.

Looking for a way to educate clients, or yourself, about the benefit of LEDs? The U.S. Department of Energy (DOE) has a great collection of technology fact sheets on solid-state lighting (SSL) topics.  For more information, check out the DOE publication page.