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Window
h
Windowsill
eld of view
(= 0.7 x h)
Figure 3. Sensor placement.
Y (cm)
Field of view
120
90
60
30
0
100
150
200
h (cm)
Figure 4. Sensor mounting height from window sill (Y) vs. sensor horizontal distance from
window sill (h).
9
Design-in Guide - EasyAir SNS212 MC
Photocell
250
300
Light sensor
The light sensor is a photo diode that reads the average light
level captured under an angle of approximately 40°. This
level depends on the amount of artificial and/or natural
light supplied in the office, as well as how this light is
reflected toward the ceiling/sensor. The EasyAir SNS212 MC
converts the illuminance signal into ON/OFF or dimming
commands to the Philips Xitanium SR LED driver in order to
maintain a constant light level on the desk.
The sensor should be installed with a minimum distance of
0.6 m to the window to avoid the sensor looking outside.
When the sensor is mounted too close to the window it will
look partly outside. Sun reflection from cars or snow can
reflect directly into the sensor. The sensor will then measure
such high illumination levels that it will drive the artificial
light to its minimal level or even switch off the artificial
lights. The optimum distance [Y] from the window to EasyAir
SNS212 MC can be obtained from Figure 4. This graph shows
the relation between the horizontal distance from the
window to the sensor [Y] and the height [h] of the sensor (h,
vertical height of the sensor measured from the window sill).
LED indicator
The product contains a LED indicator. This is enabled by
default, and it can be disabled through the app. The
behavior of the LED is as follows:
Yellow LED on: = vacancy & light sensor are functional.
Red LED on: = motion is detected and hold time is not
expired yet.
April 2023
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