Bosch Appliances Home Security System DS938Z User Manual

6  © 2012 Bosch Security Systems, Inc.

ON: 

Allows the Alarm/Test LED to operate when activated by  

 

 

 motion.
OFF:  The LED will not operate on alarm activation, but will  

 

 

 

indicate a supervision trouble condition.

Sensitivity modes depend on the type of coverage desired and the installa-

tion environment.

Figure 4.1: Selecting features

Figure 3.1: Wiring to terminals

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.
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. 

The DS938Z has several features that are controlled using the confi guration 

switches.

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1 ON        = 

ON

1 OFF      = 

OFF

LED 

Sensitivity 

Motion
Monitor 

OPEN

4 ON      and   5 OFF     =     4 Day 
4 OFF     and  5 ON      =   30 Day 
4 OFF     and  5 OFF     =  Disabled

2 ON     and 

3 OFF     = High

2 OFF   and  

3 ON      = Intermediate

2 ON     and 

3 ON      = Standard

–

+

RELAY

1

2

3

4

5

6

7

8

6 to 15

VDC

Alarm

TROUBLE

INTERFACE

PINS

KEY GUIDE

TAMPER

 F.01U.263.663 | 01 | 05.2012 | 7

Sensitivity:  Tolerates environment extremes on this setting, 

but requires the largest amount of intruder motion to achieve an alarm.

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.

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.

If both switches are in the OFF position, the unit will default to the inter-

mediate setting.

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).

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.
• 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.

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.

Setting the DS938Z for Low Gain reduces the coverage area to 40 ft. 

(12.2 m) in diameter.

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.

2.  Attach a Sonalert to the sounder pins at this time if one will be used 

during walk testing.