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Rev. A.2, 10/03 Page-8
lock and if it’s fail secure, the switch will need to send power to the lock. Figure 6 shows how to
add external contacts for non timed remote release of the lock for both lock types.
FIG. 6: ADDING EXTERNAL CONTACTS FOR FAIL SAFE AND FAIL SECURE LOCKS
NC1
C1
AC IN
F DC IN /OUT
+
FAIL
SAFE
LOCK
+
C
N
C
MOV
FOR NON-TIMED REMOTE
RELEASE OF FAIL SAFE
LOCK, PLACE NC CONTACTS
IN CIRCUIT AS SHOWN
NO1C1
AC IN F
DC IN /OUT
+
FAIL
SECURE
LOCK
+
C
N
O
MOV
FOR NON-TIMED REMOTE
RELEASE OF FAIL SECURE
LOCK, PLACE NO CONTACTS
IN CIRCUIT AS SHOWN
3.6 THE REX FUNCTION
Often, when the DK-26 is used, provision must be made to allow
people to use the door freely from the inside. If an electric strike
is used, exit may be accomplished by purely mechanical means
(turning the doorknob). If, on the other hand, a solenoid
operated or electromagnetic lock is used, free exit is only
possible if a switch on the inside releases the lock.
Connection of this switch or switches is most easily
accomplished by using the DK-26's REX input terminal (see Figure 2). REX stands for
Request To Exit. When a normally open switch activates the REX terminal, the DK-26's control
relay will open the lock for the amount of time programmed into the DK-26's timer. The result is
the same as if the DK-26 was used from the outside of the door. The REX terminal is activated
by being connected to the SRC (voltage source) terminal. It will also activate if +12 or +24V
is input to the terminal from the DK-26’s external power supply. The drawing to the right
shows the simplest connection to an external normally open momentary switch. Any number of
additional switches could be connected in parallel so that pressing any of them would activate
the REX function. An example of when this multiple switch capability is used would be an
installation with an exit button at the door and a second one at a receptionist’s desk for example.
Either could open the door for the programmed time.
There are some special characteristics as to how the REX input works. First, it does not start
the timer when the input is closed but rather when it reopens. This means that you can
use the REX input to release the door for an extended period of time. As long as terminals
REX and SRC remain connected, the lock will be released. When they disconnect, the lock will
remain released for the amount of time programmed. This extended release capability is useful
in certain applications. The REX input is also retriggerable. This means that if the lock has
been released and the REX input is triggered, the release time will be extended to the full value
that has been programmed.
SRC
REX
A
N N.O. SWITCH
CLOSING BETWEEN
"SRC" AND "REX"
CAUSES TIMED
RELEASE OF THE
DOOR.