Assa DK-26 manual Adding External Contacts for Fail Safe and Fail Secure Locks, REX Function

AN N.O. SWITCH CLOSING BETWEEN "SRC" AND "REX"

CAUSES TIMED RELEASE OF THE DOOR.

SRC REX

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

	AC
	IN
	F
	DC IN
+	/OUT

FOR NON-TIMED REMOTE RELEASE OF FAIL SAFE LOCK, PLACE NC CONTACTS IN CIRCUIT AS SHOWN

NC

NC1 C1	+	FAIL
	MOV	SAFE
		LOCK

	AC
	IN
	F
	DC IN
+	/OUT

FOR NON-TIMED REMOTE RELEASE OF FAIL SECURE LOCK, PLACE NO CONTACTS IN CIRCUIT AS SHOWN

NO

C1 NO1	+	FAIL
	MOV	SECURE
		LOCK

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.