Devices for colour control (DT-8)
Manual DALI gateway S64 KNX/S128 KNX
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The points on this so-called black bodyline (BBL) are usually defined via a colour temperature in
Kelvin. This makes it possible to exactly determine the white tone of a light between warm and
cool with just one value. The colour temperature principle is therefore perfect for the control of
white light fixtures (tunable white).
DT-8 operating devices set the required colour temperature on an LED module by mixing cool
and warm white LEDs. Of course, as before this is only possible within certain physical limits.
With today’s LED modules colour temperatures between 2000 and 8000 Kelvin are common.
4.4
Colour dislay via 3 or 4 colour channels (RGBWAF)
Principally, a colour is created by mixing different individual colours (different white tones, RGB
or RGBW). A colour can therefore also be displayed based on the mixing ratio of different single
colours, e.g. 50 % red, 0 % green, 60 % blue. The colour definition in this case is not exact but
depends greatly on the specific, physical attributes of the LEDs used to create the colour (wave
length, intensity). Nonetheless, the indication of the primary colour percentages within a system
is useful for the relative description of a colour. In some DT-8 ballasts, the colour is set by
stating 3 (RGB) or 4 values (RGBW) between 0 and 100 %.
According to DALI standard EN 62386-209, up to six colours (RGBWAF) can theoretically be
drawn upon. The DALI gateway KNX, however, only supports a maximum of 4 colours, in line
with the ECGs that are currently available on the market.
