Assa DK-26 DC Lock DC Power Wiring, USE of the F Terminal, Adding Other Lock Control Switches

Rev. A.2, 10/03 Page-7

FIG 5: DC LOCK - DC POWER WIRING

POWER SUPPLY

+

12 OR 24 VDC

DC POWER NEED NOT BE REGULATED

	AC
	IN
	F
	DC IN
+	/OUT

NOTE: MOV NOT REQUIRED IF

SECURITRON MAGNALOCK IS USED

IF FAIL SECURE

NC1 C1 NO1		DC FAIL SECURE
	+

OR FAIL SAFE LOCK

IF FAIL SAFE MOV

3.4 USE OF THE “F” TERMINAL

The F terminal on the power strip is not connected to

FIRE ALARM

anything.

It is

a

free terminal

with

either

of

two

AC

CONTACTS

intended

uses.

First,

on

some

complicated

TRANS-

N

installations, a large number of

wires

(generally

DC

FORMER

IN

C

C

negative)

may

require

termination.

It

can

be

convenient to run a jumper from the DC- terminal to

F

the F terminal so that the large number of negative

DC

WHEN THE FIRE

returns can be spread on to the two terminals. This

ALARM CONTACTS

avoids putting two many wires on one terminal or

IN

OPEN, ALL POWER

+/OUT

splicing into wires.

Second, some magnetic

lock

WILL BE REMOVED

installations require interface with NC contacts

FROM THE DOOR

controlled by the fire alarm system which will cut low

voltage power immediately releasing the magnetic lock for safety. The connection to the fire alarm contacts is normally made in the power supply but if you are using a plug in power supply, you’ll want to make the connection on the DK-26 CPU board where you have terminals. The presence of the F terminal makes the connection more convenient. Using the example of a plug in AC transformer, you would connect one leg of the transformer output to one AC IN terminal and the other to F. You would then connect the NC contacts from the fire alarm system to the other AC IN terminal and F. See the drawing to the right.

3.5 ADDING OTHER LOCK CONTROL SWITCHES

The drawings in Section 3.3 are valid for simple installations where the DK-26 is the only control device that can release the electric lock. Often, however, additional control devices are called for. The most common is some type of exit switch and this issue is covered in the next Section. Sometimes other control switches are needed which are not appropriate for the REX input as use of this input triggers the timed release capability of the DK-26.

A typical example would be a switch located centrally which would release the lock in response to an intercom call for example. If the lock is fail safe, the switch will need to break power to the