Page 6
Returning to operation of the REX relay, as we said earlier, it energizes 50 milliseconds before
the lock control transistor releases the lock. It remains energized as long as the lock control
transistor is continuing to release the lock. When the lock resecures, the REX relay will remain
energized for one additional second to allow the magnetic lock to fully engage and report secure
in the event that it is reporting lock status to an access control system.
FIG. 8: OPERATIONAL TIMING CHART FOR
AL-85851
REX RELAY
LOCK CONTROL
TRANSISTOR
NORMAL OPERATION: REX
RELAY DEENERGIZED; LOCK
CONTROL TRANSISTOR "ON"
(CONDUCTING)
OBJECT DETECTED
REX RELAY
ENERGIZES
5
0
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LOCK CONTROL TRANSISTOR
RESECURES LOCK AFTER
TIMER RUNS OUT
NORMAL OPERATION: REX
RELAY DEENERGIZED; LOCK
CONTROL TRANSISTOR "ON"
(CONDUCTING)
REX RELAY DEENERGIZES ONE SECOND
AFTER LOCK RESECURES
The four second timing feature of the lock control relay can be altered by changing jumper
settings (see Section 5) but the REX relay always operates 50 milliseconds before and one
second after the lock control transistor. Figure 8 shows the timing sequences.
5.
JUMPER SETTINGS
Refer to Figure 2 and note that there are 3 jumpers. They are depicted in factory set condition.
The LED logic jumper controls the logic of the bi-color LED. When left in factory set position
(jumper installed), the LED will illuminate red during a detection event and return to green in
the rest condition. Removing the jumper will reverse these colors.
The sensitivity jumper makes the unit sensitive to movement in the factory set condition
(jumper installed). It will become less sensitive when the jumper is removed. This is
sometimes advised when the unit is mounted with a loosely fitting door that leads to the exterior
of the building. If air, at a different temperature from the interior, is able to blow in
from the gaps in the loosely fitting door, the
AL-85851
may “see” this. The lock will
therefore be occasionally released with no one present. Removal of the jumper can correct the
problem at the cost of a bit slower operation. Other techniques include physically locating the
unit farther from the edges of the door and adding weather-stripping to the door.
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