Chamberlain LIFTMASTER SL920 - Manual (Page 22)

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Options
 If it is desired that the driveway
illuminate when the gate is activated, a light
delay timer may be installed. The light delay
timer will switch power on to the light for two
minutes, then shut power back off. The timer
relay is capable of switching up to 10 Amps
which will handle most flood or spot lights
available. A general hook-up diagram for the
light and timer is shown at left.
 The standard auto close timer built
into the circuit board can be adjusted to
between 0 and 45 seconds. Some installa-
tions may require that the gate must stay
open for more than 45 seconds before it
automatically closes. The extended auto
close timer may be hooked up as shown at
left. This optional timer can be adjusted to
automatically close the gate after the gate
has been open between 1 and 100 minutes.
The extended timer will add time onto the
auto close timer already on the board. For
more control, reduce the timer adjustment on
the main control board to zero seconds and
make all adjustments with the extended auto
close timer knob.
 For added safety, a warning alarm
may be installed in the gate operator to give
audible warning that the gate is in motion.
This will in some cases give extra time to get
out of the way of the moving gate. The
warning alarm is an ear piercing 120 decibel,
dual tone, piezo siren that operates on 12
Volt DC. To install the alarm, mount the siren
next to the circuit board and connect the
positive wire to terminal 12 (12VDC). Connect
the negative wire to limit switch 1 NC or limit
switch 2 NC for the alarm to sound in the
open or closed directions. Contact the
manufacturer for connecting the alarm to
sound in both directions. If the alarm is too
loud, the sound may be partially muffled by
applying tape over the two holes where the
sound comes out.
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