Securitron Magnalock Corp.
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© Copyright, 2011, all rights reserved
PN# 500-14900
Page 1
Rev. D, 06/11
SECURITRON MODEL XDT-12 AND XDT-24 EXIT DELAY TIMERS
INSTALLATION AND OPERATING INSTRUCTIONS
1. DESCRIPTION
The XDT-12 and XDT-24 are specialized exit delay timers designed to be integrated with fail safe
electric locks and switch equipped devices for delay initiation and reset. This creates a modular
door control package which fully meets American and Canadian building codes for delayed exit
(Special Locking Arrangements). See Section 3 for detailed information on these codes. As the
part numbers show, separate versions of the XDT exist for operation on 12 or 24 VDC.
The power of the XDT, however, goes considerably beyond meeting the code requirements.
Delayed exit is only one aspect of door control in sophisticated facilities. The XDT includes
optional functions that can be employed in entry control, door/lock monitoring, and authorized
immediate exit. External switches such as time clocks can also put the XDT into different modes
if delayed exit is not desired at all times.
To simplify the installer's task in understanding these instructions, we first describe delayed exit
which is the primary function of the XDT. Later sections describe the timer's optional functions.
These sections can be quickly browsed to see if any of the functions will improve the installation.
2. DELAYED EXIT FUNCTIONS
Exact code requirements for delayed exit vary somewhat in different jurisdictions. These
detailed variations will be addressed in Section 3. In general, however, delayed exit includes the
following components and sequences of operation.
In the normal condition, the door is locked. The locking device must be a fail safe electric lock
(secure when powered). It is most commonly an electromagnetic lock such as Securitron's
Magnalock. An initiate device is used to start the exit sequence. The XDT timer requires that
the initiate device includes a normally closed dry switch which opens to start the sequence. The
safest type of initiate device is one that relies on no special knowledge for operation.
Securitron's Touch Sense Bar is an excellent choice for non fire rated doors. A switch equipped
fire rated panic bar is appropriate for fire rated doors. Push buttons are also used but they may
not be acceptable to local building officials on the grounds of requiring special knowledge. Other
initiate devices include mats, curtain detectors and monitoring strikes.
Once the initiate switch opens, a nuisance delay period begins. The nuisance delay period may
be set for 1, 2 or 3 seconds. The duration of the nuisance delay period will depend on the local
code and/or on the desires of the end user. The nuisance delay function can also be disabled.
During the nuisance delay period, the XDT provides a pulsing relay output which is typically used
to operate a local alarm horn or Sonalert. This notifies the person at the door that he has
activated the initiate device. If he intends to exit, he must maintain pressure on the device until
the end of the nuisance delay period. If he releases the initiate device before the nuisance delay
times out, the local alarm signal will stop and the door will revert to normal (locked) mode. The
sole purpose of the nuisance delay function is to deal with accidental triggering of the initiate
device. It makes particular sense to employ the nuisance delay in buildings occupied by a
changing population which will not be familiar with the exit control system. Retail stores or
museums are good examples of such buildings.
Once the nuisance delay times out (or immediately if no nuisance delay has been set) the
release delay period begins. The XDT's local alarm output will go from pulsing to steady. This
will alert the person at the door that he need no longer maintain activation of the initiate device.
Once the release delay begins, it is irrevocable. The door will release at the end of the period.
Code mandated duration of the release delay period is 15 seconds although certain jurisdictions
allow extension to 30 seconds by local building or fire safety officials. The release delay period
on the XDT can therefore be set for 15 or 30 seconds and this total release delay time includes
the nuisance delay. For example, if a 2 second nuisance delay is set, the remaining release
delay will automatically be 13 or 28 seconds for a total of 15 or 30 seconds.
