TM 5-6350-262-14/7/NAVELEX 0967-466-0970/TO 31S9-4-28-1
FUNCTIONING OF EQUIPMENT
operated and latched, the closed relay contacts provide a
continuous duress alarm signal path and a return path
for current flow through light emitting diode (LED) CR1.
This chapter contains a circuit description for each of the
(Diode CR2 protects alarm switch components from
equipment operation modes (i.e., no alarm condition,
possible damage due to reverse polarity of the 20-V dc
duress alarm, duress alarm reset, and tamper alarm)
input power if input leads are improperly connected
Explanations are keyed to the alarm switch schematic
diagram shown in figure 6-1.
CR1 indicates that a duress alarm signal is present at
the output terminal strip. This duress alarm condition will
6-2. No-Alarm Condition.
exist until the circuits are reset.
A no-alarm condition exists when circuit components are
6-4. Duress Alarm Reset
restored as shown in figure 6-1. Switches S1 and S2 are
momentary or spring-return push button switches.
Once the alarm switch has been latched in the duress
Tamper switch S3 is held in the CLOSED position by
alarm condition, it must be reset to the no-alarm
proper installation of the alarm switch cover. Relay K1
condition for further use. When reset switch S2 is
contains reed contacts which are magnetically latched in
pressed momentarily, 20 volts dc is applied to the coil of
the last position in which they are operated. In this
latching relay K1B. Operation of relay K1B restores the
condition, a no-alarm signal is presented to the Alarm
relay contacts to the no-alarm condition described in
Set Control Unit C-9412( )FSS-9(V) via a circuit
impedance of 2000 ohms or less between terminals TBl-
1 and -2, and between terminals TB1-5 and -6.
6-5. Tamper Alarm.
6-3. Duress Alarm.
Tamper switch S3 opens in the event the alarm switch
cover is removed in an attempt to disarm the duress
Whenever an operator actuates duress alarm switch S1,
alarm function. The resultant high impedance of 100,
the low impedance signal patch between terminals TB1-
000 ohms or greater between terminals TB1-5 and -6 is
1 and -2 is broken. The resulting high circuit impedance
used as the tamper alarm signal output. Replacement of
of 100, 000 ohms or greater is used as the duress alarm
the alarm switch cover actuates tamper switch S3 to the
signal output. Simultaneously, 20 volts dc is applied to
closed position and restores the output to the no-alarm
the coil latching relay KLA through normally open
condition described in paragraph 6-2.
contacts of duress alarm switch S1. With relay K1A