© Interleader Limited 2017
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Printed: 06/09/2017
11 Sunset/Sunrise Switching
The MLC can be set to automatically switch the lights on at sunset and off again at sunrise in exactly
the same way as individual MIL-Star
®
lights - except that all lights will be turned on or off together.
When switched to this mode in daylight, the Battery Capacity LEDs will light as normal and MIL-Star
®
lights will be set off. When the light level becomes less than 400 Lux (the level of light at sunset on a
clear day) the defined channel will be turned on. Note that it is the light level that turns the lights on and
off, not the time of day. Very overcast conditions causing a dark sky may cause light levels to drop
significantly below 400 Lux even though the time is not at sunset. This will cause the MLC to switch
lights on (see test results below).
The MLC monitors
light level continuously and if the ‘sunrise’ light level of 500 Lux is exceeded, the
lights will be turned off again. This may lead to a situation where if the MLC is set to automatic and
before sunset a large black cloud causes the lights to be turned on, but then moves away, they may go
back off again (as happened in the test below).
The graph below shows the drop in light level from 60 minutes before sunset to sunset. The green bars
indicate the actual time the test set of lights came on. MLC results would be similar.
Meteorological conditions at time of test:
Metar from nearby Stansted Airport (EGSS) at 17:20 Zulu, 20
th
February 2016:
Overcast clouds at 1400 feet (recent rain and drizzle). Temp. 11C, Dewpoint 9C, RH 87% 1006hPa.
MIL-Star
®
- Sunset Switching Test
