Dummy Load; Introduction; Set The Jumper Jp1 On The Dummy Load; Installation - Bosch Plena Installation And User Instructions Manual

Plena Voice Alarm System | Installation and User Instructions | Equipment
15

Dummy load

15. 1

Introduction

The Dummy Load has these functions:
• Increases the percentage of impedance (with
respect to the cable impedance) present at the
end of the line.
• Allows more loudspeakers to be fitted.
• Allows longer cable lengths.
Fault detection of the loudspeaker lines with impedance
measurement is triggered by a change in excess of 20%.
The impedance at the end of the loudspeaker line must
be more than 20% of the total impedance to make sure
that an open circuit is detected.
The Dummy Load has a jumper to set the load at
20 kHz to 8, 20 and 60 W.
15.2 Set the jumper JP1 on the
Dummy load
Note
You can find the Dummyload calculator.xls on
the Plena Voice Alarm CD.
1 Use the Dummy Load Calculator to calculate the
jumper setting of JP1 on the Dummy load.
2 Select the Excel sheet Dummyload calculator. Click
on Enable Macros when the dialog box appears.
The worksheet opens.
3 Type the load per loudspeaker in Step 1. The
maximum number of loudspeakers is automatically
calculated and appears in Step 2.
4 Type the number of loudspeakers in the line in
Step 2. The result automatically appears in Step 3.
5 Type the capacitance of the 100 V cable in Step 4.
6 Type the length of the cable in Step 5.
7 Click Display jumper JP1 settings. The configuration
of the jumper settings appears.
8 Set the jumper JP1 on the Dummy load to the shown
in the calculator.
15.3

Installation

To install the Dummy load do as follows:
1 Connect the two leads onto the connection terminals
of the last loudspeaker in a line.
2 Attach the Dummy Load circuit board in the
loudspeaker cabinet to the mounting studs.
Bosch Security Systems | 2006-06 | 9922 141 10377 en
Note
In some loudspeakers only one mounting stud is
available as the studs are too far apart.
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