Securitron MUNL-24 - Manual (Page 7)

PN# 500-18800
Page 7 Rev. E, 11/11
Note that if the door is heavily pre-loaded (by someone trying to pull it open before the Mortise
UnLatch has released it for example), the Mortise UnLatch may not possess enough power to
release the door. This is termed a stall condition for the motor. When a motor is stalled for a
period of time, it can be damaged by heat build up as motors draw heavy current when they’re
not permitted to move. The Mortise UnLatch automatically detects any stall condition
that persists for more than 1.5 seconds and shuts itself off. To operate, the Mortise UnLatch
must simply be triggered again (which is the normal action for anyone who has failed to enter).
4. WIRING
4.1 GENERAL ELECTRICAL CHARACTERISTICS
The Mortise UnLatch is a six wire device. Power (12 or 24VDC depending on the model) is
applied to the red and black wires observing polarity and power should be continuously
present on these wires. If you connect power in reverse, the Mortise UnLatch will not
operate but it will be damaged if left connected for an extended period of time. To
operate the Mortise UnLatch, the trigger wire (orange) is connected to the red wire (+V) via
an external switch. When this connection is made, the Mortise UnLatch will release the door and
keep it released so long as the red and orange wires are connected. When connection between
these wires is broken, the door will be resecured (once it recloses). In certain applications the
door is released all day and secured all night. There is no problem operating the Mortise
UnLatch in this manner (continuous duty) but it is more common for the door to be released for
only a few seconds at a time for controlled entry. This is typically done by relay contacts which
close from an external card reader, digital keypad or keyswitch. The external control device
includes a timing function which will operate the Mortise UnLatch for a few seconds to permit
each entry. Like most conventional electric strikes, the Mortise UnLatch is fail secure which
means that it will maintain the door in a secure position if power is lost. Entry is not possible
(except with a key) but people can, of course, exit by simply turning the door handle or knob
from the inside.
FIG. 7: MORTISE UNLATCH WIRING
WHITE (STATUS: COM)
BLUE (STATUS: N.O.)
CLOSURE
BETWEEN +V IN
AND TRIGGER
RELEASES LATCH
+ -
ORANGE (TRIGGER)
GREEN (STATUS: N.C.)
POWER SUPPLY
RED (+V)
BLACK (NEG)
UNLATCH
POWER SHOULD BE CONSTANTLY CONNECTED
DC
In normal operation, the Mortise UnLatch draws about 600 mA @ 12 VDC or 300 mA @ 24VDC
when it operates (the plungers are moving) and a steady 40 mA at all times. Note that
regulated input voltage is not required to operate the Mortise UnLatch. Full wave rectified DC
is acceptable (transformer + bridge rectifier). When using a MUNL-24 with a 24VAC
transformer (TP-24-2) and bridge rectifier (BR-7) two additional components are required.
These are two zener diodes (1N5333B, 5 watt, 3.3 volt or equivalent) that you will find in a
package separate from the hardware pack. Because the peak voltage of a transformer and
bridge rectifier combination can be as high as forty volts the diodes are required to drop the
peak voltage into the operable range for the MUNL-24. The following diagram (Figure 8) notes
installation placement of the zener diodes.