Nuisance Alarms - TM-5-6350-262-14-20020

TM 5-6350-262-14/2

NAVELEX 0967-LP-466-9021

TO 31S9-4-35-1, Chg 1

(7) Remove the multimeter test leads and

(1) Remove the cover (fig C-1) from the

reconnect the temporarily removed lead to termi-

processor and pull the tamper switch (fig. 1-1)

nal 5 of TB1 (fig. 1-1).

plunger out to complete the circuit in this en-

closure.

b. Processor/Receiver Ultrasonic Passive Sig-

(2) Temporarily remove the lead from termi-

nal Adjustment. Initial adjustments and checkout

nal 5 of TB1 (fig. 1-1) that goes to the J-SIIDS

is performed with the processor/transceiver

control unit.

ultrasonic motion signal (if used) disabled and

(3) Connect a multimeter (AN/USM-210 be-

the band rejection filter in the processor by passed.

tween terminals 2 and 5 of AB1 (fig. 1-1). With

(1) Connect the multimeter AN/USM-210)

the covers secured to all the receiver enclosures

positive lead to the MV (fig. 1-1) test point and

and the tamper switch plunger of the processor

the negative lead to signal ground (terminal 8 of

pulled out the continuity should be approximately

TB1, fig. 1-1). Set the multimeter to read D.C.

that indicated in table 2-2 for the wire size used

and the selector switch to 50V.

and the approximate cable run distance.

(2) Perform the applicable steps in para-

graph 2-8d (3) and (4) to check out the proces-

NOTE

sor/receiver ultrasonic passive signal without the

The approximate resistance per 1000 feet

processor/transceiver ultrasonic motion signal

for various wire sizes is given in table

operating (if used) and then with the processor/

2-2. Double the approximate wire run

transceiver ultrasonic motion signal operating.

distance to each unit to account for com-

pleting the tamper loop.

2-15. Nuisance Alarms

If the processor/receiver ultrasonic passive sig-

Table 2-2. Wire Resistance Per 1000 Feet

nal experiences an excessive number of nuisance

Wire

Ohms Per

alarms the cause must be investigated. A probable

Size

1000 feet

cause is sources and entry points of ultrasonic

4.1

energy in the protected area. Possible sources are

6.5

10.35

motors, fans, bells, buzzers, and horns operating

16.46

*22

during periods when the area is secured. Pos-

sible entry points are ducts, vents, cracks in walls,

*Suggested wire size (MIL-W-76)

floors, ceilings, around windows and under doors,

and similar points where the flow of air or the

(4) Remove the enclosure cover unit (one at

wind may inject ultrasonic energy. As an aid in

a time) and verify that the continuity goes to

locating ultrasonic energy sources and entry

infinity (open circuit). The switch should open

points, a receiver with only its receive cable con-

with no less than 1/8 inch nor more than 1/4 inch

nected (receiver terminals 1 and 2) may be used

of cover displacement. If the switch fails to meet

as a "sniffer" in the conduction of a noise test,

these requirements report malfunction to direct

support (intermediate) maintenance. P u l l t h e

(para 2-8c(5). By systematically moving the

sniffer receiver throughout all parts of the pro-

tamper switch plunger out and verify that the

tected area one may locate points of excessive

continuity is complete and the resistance approxi-

ultrasonic energy. Cracks in floors, walls and

mates that of the established tamper circuit.

Fasten the cover to the enclosure and again verify

ceilings and around window and door frames

that the continuity is complete and the resistance

should be caulked and weather stripping around

approximates that of the tamper circuit.

doors and windows should be installed or replaced

(5) Repeat (4) above for each of the en-

as appropriate. Air conditioning and heating

closures.

ducts should be baffled. If such measures do not

(6) To simulate the cover on the processor

produce acceptable noise test results it may be

enclosure use a straight edge across opposite side

necessary to relocate some receivers and consider

of the enclosure to depress the tamper switch

adding receivers to the system with some or all

plunger (fig. 1-1). The switch plunger should

receivers having reduced GAIN settings. After

meet the same requirements as outlined in (4)

relocation or addition of a receiver the noise and

above. Verify that the continuity is complete and

simulated forced penetration tests must be

the resistance approximately that of the tamper

circuit.

performed.

2-11

Change 1