5.48 General Catalogue • Modular Devices • Technical
Light Sensitive Switches
Light Sensitive Switches
Using light sensitive switches can prevent the unnecessary use of
lighting circuits where suf cient daylight exists. The bene t of
modular devices is the facility to set the ambient lighting level at
which the device will operate, and as the device is tted at the
distribution point prevent unauthorised tampering. The remote pho-
tocell unit can be mounted up to a distance of 50 metres from the
device. Two devices are available the standard EEN100 light sensitive
switch and an enhanced programmable version the EE171 that also
allows time clock control.
Principle of Operation
Both devices control lighting systems according to natural
illumination;
• The user sets the working level:
• The photo cell measures the external light level
The output of the EEN100 is:
• ON, when the measured level is lower than the pre-set
light level
• OFF, when the measured level is higher than the pre-set
light level
The output of the EE171 during the programmed ON time period is:
• ON, when the measured level is lower than the pre-set
light level
• OFF, when the measured level is higher than the pre-set
light level
The output of the EE171 during the programmed off time period is:
• OFF, regardless of the lighting level
The light sensitive switches include a built in time delay which avoids
unnecessary switching due to temporary factors such as car
headlight beams etc...
Description
The programmable light sensitive switch EE171 has two main
functions:
• Light sensitive switch comprising
1 Override selector switch to allow permanent ON or OFF, auto or
test mode
2 Lighting range selector
3 Potentiometer to set light level
4 Indicator to show output switching status
• A programmer to establish the automatic operating cycle
The programmer comprises 4 keys:
5 to choose whether the circuit is on or off.ON / OFF
6 to set the program and scroll program stepsProg
7 Reset
8 and to change settings+ -
