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F-710-017, V1.2 TCM 330 / TCM 330U User Manual | v1.1 | August 2016 | Page 34/62
USER MANUAL V1.1
TCM 330 / TCM 330U
Wireless LED Controller Module
4.6.1
Functional behaviour of wireless light level sensors
Wireless level sensors are used to adjust the light level based on available natural light.
The fundamental idea is that less artificial lighting is required if sufficient natural light is
available. The concept of controlling the light level based on the amount of available natural
light is called “daylight harvesting” and enables significant energy savings.
This approach is also referred to as “Open Loop Dimming” since it considers only the avail-
able natural light for regulation and does not measure the combines (n artificial)
light level.
In contrast, “Closed Loop Dimming” (sometimes also called Constant Light Dimming)
measures the total available light (natural and artificial) and tries to keep this level con-
stant.
Closed loop dimming is a much more complex approach and relies on the ability to exactly
measure the combined light level at the place where it is needed (e.g. office desk) which is
not trivial. It can also result in noticeable variations in the light level which is not desirable.
Open loop dimming has therefore been chosen for EnOcean LED zone controllers.
LED zone controllers receive information about the amount of available natural light from
one linked light level sensor using EnOcean Equipment Profiles (EEP) A5-06-02 or A6-06-
03.
For correct operation it is essential that the light level sensor reports only natural light and
is influenced as little as possible by artificial light. The light level sensor should therefore be
placed at a position facing the window or skylight where it is not or only minimally influ-
enced by light from the fixtures.
Two different dimming modes are possible based on light level sensor input:
n
Five point (continuous) dimming
In this mode, the user (or installer) can define the relationship between output light level
and available artificial light reported by the light level sensor based on a dimming curve
with five supporting points.
This mode is commonly used for indoor lighting as it enables smooth dimming which is
barely noticeable to the user.
n
Two level (ON / OFF) dimming
The light level sensor can alternatively be used to activate an automatic switching mode
between MaxVoltageLevel and MinVoltageLevel based on light intensity.
One typical application is a twilight switch where the light will automatically be turned
ON during darkness.
The default operation mode is five point dimming. Two level dimming can be enabled by
setting DaylightingMode accordingly. Both modes are described in more detail now.
