Chamberlain LIFTMASTER SL920 - Manual (Page 5)

5
Features
     OPERATION
The SL920 Full Systems Capability can operate in a AUTO CLOSE TIMER (TIMER ON) or a
PUSH-TO-OPEN/PUSH-TO-CLOSE (TIMER OFF) mode of operation. In the AUTO CLOSE TIMER
mode of operation the operator is given a command to open the gate and hold it open until the input is
released and until the auto close timer has elapsed at which point the operator will close the gate
automatically. In the PUSH-TO-OPEN/PUSH-TO-CLOSE mode of operation each time a signal is sent to
the operator, it will cause it to do the opposite of what it did before. (i.e., If the gate is closed, it will start
opening, if it is open, it will start closing: If it is closing, it will REVERSE TO OPEN, if it is opening, it will
REVERSE TO CLOSE.)
     CONTROLS
The SL920 Full Systems Capability works with the following control devices: Key switches, Push
buttons (separate or intercom), numerical key pads and any peripheral equipment which can supply
normally open or normally closed contacts as well as optional radio transmitters and receiver (specified
by and available from the manufacturer). These contacts can be connected to the operator input terminals
to perform the opening, close, safety, or the stop functions.
     AUTO CLOSE TIMER
The operator comes factory preset with the auto close timer turned OFF. The auto close timer will
close the gate automatically after a specific amount of time has elapsed. The amount of time can be
easily adjusted between 0 and 45 seconds by turning a small "pot" located on the right edge of the circuit
board (See page 17). The timer can be disabled or activated by flipping a single switch located on the
top right edge of the circuit board. If the timer will be used it is recommended that some type of
supplementary safety device be installed. If more time is required, there is an extended timer available
from the manufacturer allowing up to 100 additional seconds (See Options).
     MANUAL RELEASE SWITCH
This simple on-off switch is built into the operator. In an emergency, EVEN WITH THE POWER
OFF, the gate can be pushed open manually after flipping the switch from Operate to Release. This
switch may also be removed and placed externally from the machine.
     GATE SENSITIVITY ADJUSTMENT FOR SYSTEM PROTECTION
The amount of force necessary to stop the gate can be adjusted to conform to the various sizes
and weights of any particular gate. When adjusting the sensitivity, the operator can be given only as much
energy as is necessary to overcome the resistance of the gate. If the gate should strike an obstruction in
either direction, the gate will reverse. If the gate should again strike an obstruction before reaching a limit,
the gate will stop, remain stopped, and will sound an alarm. (See page 17)
     MASTER AND SECOND
Some very large entrances may require the use of two gates. If this is the case, the two gates can
be easily automated using the "master and second" configuration. This configuration uses two gates and
two operators in ONE driveway. The operators used are two regular SL920 Full Systems Capability
operators one of which is of standard "right hand operation" and the other which is easily converted to
"left hand operation" by flipping a single switch located at the top of the circuit board (See page 17).