Copyright© 2007 Watt Stopper/Legrand
®
07076r2 4/2007
LightSaver
®
LS-101 Daylighting
C o n t ro l l e r
Figure 3: LS-101 Field of view, sidelight application
When the primary source of daylight is a skylight (to p l i g h t i n g ) ,
t h e re are seve ral options for mounting the LS-101. The
re commended mounting lo cations are shown in Figure 4.
I d e a l ly, the sensor is mounted on the South sidew a l l
looking North acro ss the light well.
It could also be mounted on the ceiling next to the
skylight, looking down at the flo o r.
A skylight may pro d u ce 5000 fo o tca n d les or more. If the
sensor is mounted so that it looks up into the skylight, the
daylight will exceed the maximum OFF setpoint of 1275fc
which is too low for this orientation.
Figure 4: LS-101 Skylight application
Figure 1: LS-101
SPECIFICATIONS
Light Sensor range . . . . . . . . . . . . 1 to 1400 fo o tca n d le s
ON Setpoint range . . . . . . . . . . . . . . 1 to 850 fo o tca n d le s
A u tomatic Deadband. . . . . . . . . . . 25%, 50%, 75%, 100%
S tatus Indica tor . . . . . . . . . . . Multi-function green LED
Power re q u i rements . . . . . . . . . . 12/24 VDC, min 10 mA
To tal power re q u i rements are dete r m i n e d
by the co n t ro l led dev i ce .
Output signal . . . . . . . . . . . . . . . 12/24 VDC, max 120 mA
L o ca t i o n . . . . . . . . . . . S u i ta b le for dry, interior lo cations
E n v i ronment . . . . . . . . . 50° to 104° F, le ss than 90% rh
Dimensions . . . . . . . . . . . . . 2 . 4” diameter x 0.7” depth
(61mm x 17mm)
DESCRIPTION
The Watt Stopper LS-101 is an interior photosensor that
a u to m a t i ca l ly turns a zone of lights ON and OFF based on
daylight levels. It is a low vo l tage dev i ce intended to
signal a power pack or relay panel.
The LS-101 is designed
to re q u i re minimal
a d j u stment at sta r t u p .
For more adva n ce d
a p p l i cations, an
o n b o a rd display and
t wo pushbuttons allow
for adjustments, if
needed. The display is
hidden under a re m ova b le
cove r. To ass i st with adjust m e n t ,
the LS-101 displays the current light
level re a d i n g .
Figure 2: Cover removed
The LS-101 is designed to be either ceiling- or wall-
m o u n ted. It has a wide range light sensor ca p a b le of
measuring from 1 to 1400 fo o tca n d le s .
SELECTING A LOCATION
The LS-101 co n t rols lights in areas that re ce i ve enough
daylight so that the electric lights can be re d u ced or
s w i tched OFF. It is important to select a lo cation for the
L S-101 where the daylight is re p re s e n ta t i ve of the
daylight throughout the co n t ro l led zone. Note the path of
s h a d ows. Daylighting co n t rol will be pro b lematic if part of
a co n t ro l led zone is in shadows while another part has
p lentiful daylight.
When the primary source of daylight is a window
(sidelighting), the LS-101 is typica l ly ceiling mounte d
within the daylit zone which ex tends 12 feet or le ss in
f rom the window. A good lo cation is often between the
w i n d ow and the first row of fix t u res. Figure 3 shows a
t y p i cal mounting lo cation for a sidelit applica t i o n .
