Ceiling Mount
PIR Detector with Self-Test
DS938Z
en Installation Guide
Reading Bosch Security Systems, Inc. Product Date Codes
For Product Date Code information, refer to the Bosch Security Systems, Inc.
© 2012 Bosch Security Systems, Inc. 130 Perinton Parkway Fairport, NY 14450
If the time period selected has elapsed from the last alarm, the LED will
1 Overview
flash two times and the Trouble Output will activate.
The DS938Z is a high performance passive infrared intrusion detector. It is
equipped with advanced PIR detection and supervision circuits and is de-
signed to provide an alarm condition upon detection of an intruder passing
through its area of coverage.
Setting the Motion Monitor timer to shorter periods can be used to force a
protection walk test of remotely located zones.
It is recommended that the 30 day timer be selected. This verifies that the
unit is operational and avoids nuisance trouble conditions caused by holi-
days, vacations, etc.
Employing balanced dual-opposed sensing elements, the DS938Z passive
infrared (PIR) detector makes use of the fact that all objects give off (emit)
infrared energy, and that the warmer an object is, the greater the amount
of infrared energy given off. The DS938Z uses PIR receiver technology
designed to detect the change in infrared energy caused when a target of a
different temperature from a stable background passes through its field of
coverage.
7 Optical Module
7.1 Optical Module Masking
Peel-off masks are provided with the unit for each segment of the opti-
cal module to allow for customized coverage, or to block out areas of
objects that may cause thermal disturbances. The mask is self-adhesive
and pre-cut in the shape of the optical module.
The location of the zone to be masked depends on the position of the
detector. Therefore, determine the mirror surface to be masked before
removing the mirror from the detector.
To block out a particular zone or group of zones, peel off a section of
the mask that corresponds to the appropriate zone, and stick it on the
mirror segment. Before attempting any masking, be sure the chosen
mirror surface is the correct one. Refer to Figure 7.1 to identify mirror
segments and zones.
The coverage pattern consists of sensor zones arranged to form a circular
coverage pattern.
Using Motion Analyzer II circuitry, the detector must first see a change in
infrared energy in one zone followed by a change of energy in the remain-
ing zone. Therefore, disturbances that occur in only one finger do not
constitute motion and are ignored. This “catch sensitivity” may be changed
in the field by the installer to provide the degree of sensitivity required by
the installation.
Self-test and supervision circuits provide reliable operation in a variety of
installation environments. The result is a highly advanced detector offering
superior performance with freedom from false alarms.
Specifications
NOTICE!
Dimensions 3.5 in. x 5.25 in. (8.9 cm x 13.3 cm)
(HxDia)
When disabling the look-down segment, do not mask segment 5 direct-
ly as this will disable the entire detector. Instead, mask the segment on
the dome directly below segment 5.
Input
6.0 to 15.0 VDC; 5 mA standby, 20 mA in alarm with LEDs enabled. Use only an Approved
Limited Power Source.
Power
Alarm Relay Silent-operating Form “C” relay. Contacts rated <100 mA, 25 VDC, 2.5W maximum, <20
Ohm closed for DC resistive loads.
TOP VIEW
A
SIDE VIEW
AR8-13
Tamper
Contacts rated at 28 VDC, 125 mA maximum, <1 Ohm. Connect tamper circuit to a 24-
hour protection circuit.
A
P
B
B
P
O
C
O
C
Trouble
Output
Maximum current load is 25 mA.
D
N
N
D
E-4
M-4
M
E
M-3
M-2
M-1
5
E-1
E-2
E-3
Optional
TC6000 test cord.
M
E
Accessory
L
F
G
L
K
F
J
H
A R 8 - 1 3
I
K
G
J
H
I
1
2
3
4
5
4
3
2
1
Figure 7.1: Mirror module to pattern reference
NOTICE!
When attempting to remove any masking, many adhesives will either
destroy the mirror surface or leave enough residue behind to reduce
coverage performance.
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6.2 False Alarm Prevention
2 Mounting
Turn on all heating and cooling sources that would normally be in opera-
tion during times of protection. Stand away from the unit and outside the
coverage pattern, then monitor the background noise for at least three
minutes.
Select a location likely to intercept an intruder moving beneath and across
the coverage pattern. Refer to Figure 2.1. Recommended mounting height
range is 8 to 18 feet (2.4 to 5.5 m).
The surface should be solid and vibration-free. (i.e. Drop tiles should be
secured if the area above the tiles is used as an air return for HVAC sys-
tems).
Readings should not deviate from the reference level more than ±0.15
VDC. For readings outside these limits; eliminate the cause, rotate the unit
slightly, or mask out the mirror segment(s) looking down at the thermal
disturbance.
30 ft
26 ft
30 ft
26 ft
20 ft
13 ft
7 ft
0 ft
7 ft
13 ft
20 ft
9 m
30 ft
8 m
6 m
4 m
2 m
0 m
2 m
4 m
6 m
26 ft
20 ft
13 ft
7 ft
6.3 Coverage Margin
Again walk across the farthest edge of required coverage.
≤5.5 m
4.6 m
≥4.0 m
≤18 ft
15 ft
≥13 ft
AR13-18
A minimum voltage change of 1.0 VDC from the reference level is required
in the wintertime when the background temperature is cool. This will make
up for summertime, when the background is warmer. If testing the unit in
the summertime, the minimum recommended voltage change is 0.75 VDC.
0 m
0 ft
0 ft
≤4.0 m
3.0 m
≤13 ft
10 ft
7 ft
AR8-13
4 m
≥2.4 m
≥8 ft
13 ft
20 ft
When testing is completed, remove the TC6000 Test Cord, and twist-lock
the cover into place.
0 m
0 ft
8 m
6 m
4 m
2 m
0 m
2 m
6 m
8 m
9 m
9 m
8 m
9 m
26 ft
30 ft
6.4 Supervision Feature
Figure 2.1: Coverage Pattern
The DS938Z performs several supervision features that, combined with
the advanced motion detection capabilities of the detector, provide an ex-
tremely high level of security. A supervision trouble condition is indicated
at the detector by the Alarm/Test LED (see the Supervision Display Chart).
1. Remove the base from the enclosure by pressing the two enclosure re-
lease tabs inward while lifting the enclosure away from the base. Refer
to Figure 2.2.
•
The LED indicates the cause of the supervision trouble using coded
pulses. The supervision trouble signal activates the Trouble Output
available at terminal 8, which should be connected to a 24-hour zone.
Enclosure release tabs
The supervision features function as follows:
Test lead
cutout
Interface connector
LED
CAUSE
Optical module
ON
Unit alarm
Cover twist tabs (4)
Enclosure release openings (2)
2 Flashes
4 Flashes
Motion monitor time out
PIR self-test failure
Anti-vandal
locking screw
holes (2)
PIR: The operation of the PIR is electronically checked approximately ev-
ery 12 hours. If the PIR fails, the Alarm/Test LED will flash four times and
the Trouble Output will activate.
Interface
pins
Figure 2.2: Opening cover
Motion Monitor Supervision: This feature verifies that the detector has a
clear view of the detection area and has not been blocked. When selected
using switches S4 and S5, a supervision timer is activated. A trouble con-
dition will be indicated if the detector has not alarmed at least once during
the selected time period (this feature can be disabled by placing both
switches in the Off position). The time period selected should be long
enough to allow adequate time for holiday weekends.
NOTICE!
Slightly rock the enclosure side-to-side during removal to overcome the
friction caused by the base-to-enclosure terminal pins.
2. Open the cover by turning counterclockwise.
Refer to Section 4.0 Feature Selection for proper switch settings.
3. Route wiring as necessary to the rear of the base and through the cen-
ter hole. Refer to Figure 2.3.
4 © 2012 Bosch Security Systems, Inc.
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NOTICE!
CAUTION!
The use of a Sonalert type device (sounder) will provide an audible
tone during the time the unit is in alarm. Of the three available connec-
tor pins, the center pin is positive (+) with respect to either outside pin
(outside pins are common (-)).
Be sure all wiring is unpowered (de-energized) before routing.
ANTI-T AMPER SCREW HOLE
REQUIRED FOR EN50131
INST ALLA TIONS
Use of the sounder is intended only as an aid for walk testing during
installation.
ALARM/TEST LED
INDICATOR (3)
SOUNDER
TEST LEAD
CUTOUT
NOISE
VOLTAGE
TERMINAL
STRIP
REAR WIRE
ENTRANCE
3. Place the cover on the unit, and twist-lock it clockwise into place.
NOTICE!
LO
HI
Be sure the TC6000 and Sonalert leads are dressed through the cut-
out.
WIRE
TIE-DOWNS (2)
MOUNTING
SLOTS (4)
INTERFACE
PINS
GAIN SELECT
JUMPER
COVER
TAMPER
4. Apply power to the unit.
CONFIGURATION
SWITCHES
5. Wait at least two minutes, after applying power, to start walk tests.
Mounting Base
ANTI-TAMPER SCREW HOLE
REQUIRED FOR EN50131
INSTALLATIONS
Top View of Enclosure
with Cover and Optical Module Removed
NOTICE!
Walk testing should be done across the coverage pattern as shown.
Figure 2.3: Overview
4. Firmly mount the base. Depending on local regulations, the base may
be directly surface mounted using anchors, mollies, or wing-nuts, or
may be mounted to standard 4-inch octagonal or square electrical
boxes.
6. The edge of the coverage pattern is determined when the Alarm/Test
LED indicator (and optional Sonalert®, if installed) first turns on.
7. Walk test the unit from all directions to determine the boundaries.
8. After completion of the walk tests, remove the Sonalert® (if installed).
NOTICE!
The DS938Z base will not completely cover a 4-inch square box. Where
aesthetics are important, a 4-inch octagonal box is recommended.
6 Final Tests
6.1 Noise Measurement
NOTICE!
NOTICE!
Mounting to removable ceiling tiles is not recommended unless a
sandwich is made of the base, ceiling tile, and a back plate behind the
tile. Covers used for 4-inch octagonal and square boxes make a suitable
back plate (when used with bolts and wing nuts, as an example).
Meter readings are very important in determining background distur-
bance levels and catch margin sensitivity.
1. Connect a 20,000 ohm/volt (or greater) DC VOM to the Noise Voltage
connector using the TC6000 as shown. Set meter scale for about 3.0
VDC.
3 Wiring
2. The base reference level for reading background noise or target volt-
ages is approximately 2.0 VDC. Installations in quiet environments,
therefore, will result in a steady meter reading between 1.9 and 2.1
VDC. Look for areas and sources of thermal disturbances if the meter
fluctuates greatly.
CAUTION!
Only apply power after all connections have been made and inspected.
Do not coil excess wiring inside detector. Use no smaller than #22
AWG (0.8 mm) wire in the terminal strip.
8 © 2012 Bosch Security Systems, Inc.
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•
•
Standard Sensitivity: Tolerates environment extremes on this setting,
but requires the largest amount of intruder motion to achieve an alarm.
KEY GUIDE
INTERFACE
PINS
Intermediate Sensitivity: The recommended setting for most instal-
lations. Use in locations where an intruder is expected to cover only a
small portion of the protected area. Tolerates normal environments on
this setting. The detector is shipped in Intermediate Sensitivity mode.
1
2
3
4
5
6
7
8
–
+
•
High Sensitivity: The setting for fast response to intruder signals. For
use only in extremely quiet environments where ceiling drafts, and
thermal and illumination transients are not anticipated.
6 to 15
VDC
Alarm
RELAY
TAMPER
Figure 3.1: Wiring to terminals
If both switches are in the OFF position, the unit will default to the inter-
mediate setting.
Terminals 1 (-) & 2 (+): Power contacts.
Terminals 3 (NO), 4 (C), & 5 (NC): Alarm relay contacts. Use terminals 4
& 5 for Normally Closed circuits. Do not use with capacitive or inductive
loads.
NOTICE!
Although the sensitivity modes provide different degrees of tolerance
to environmentally caused alarms, the installer should assure peak
background noise voltage readings do not exceed ±0.15 VDC. (See
Section 8.0 Final Tests).
Terminals 6 (T) & 7 (T): Normally Closed tamper contacts.
Terminal 8 (TR): Solid state Trouble output. Shorts to ground (-) when the
detector is in a Trouble condition.
4.3 Signal Gain
The DS938Z permits selection of the signal gain depending upon the
environment to be protected. The gain select jumper is located under the
optical module. Refer to Figure 2.3.
4 Feature Selection
The DS938Z has several features that are controlled using the configuration
switches.
•
High Gain: Recommended for large coverage applications up to 60
ft. (18.3 m) in diameter. The DS938Z is shipped in this setting. If
the gain select jumper is missing, the unit will default to High Gain.
4 ON and 5 OFF
4 OFF and 5 ON
4 OFF and 5 OFF = Disabled
=
=
4 Day
30 Day
Motion
Monitor
•
Low Gain: Recommended for applications where the area to be cov-
ered is 40 ft. (12.2 m) or less in diameter and for applications where
High Gain may be too sensitive for environmental extremes.
2 ON and 3 OFF = High
2 OFF and 3 ON = Intermediate
2 ON and 3 ON = Standard
Sensitivity
1 ON
1 OFF
=
=
ON
OFF
NOTICE!
Setting the DS938Z for Low Gain reduces the coverage area to 40 ft.
(12.2 m) in diameter.
OPEN
5 Setup and Walk Testing
Figure 4.1: Selecting features
1. Attach a TC6000 Test Cord to the Noise Voltage terminals. Since the
outside terminals are common, polarity is not important and the black
lead may be toward or away from the optical module.
4.1 LED Operation
ON:
Allows the Alarm/Test LED to operate when activated by
2. Attach a Sonalert to the sounder pins at this time if one will be used
during walk testing.
motion.
OFF: The LED will not operate on alarm activation, but will
indicate a supervision trouble condition.
4.2 Sensitivity Selection
Sensitivity modes depend on the type of coverage desired and the installa-
tion environment.
6 © 2012 Bosch Security Systems, Inc.
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