Bosch PRAESENSA Installation Manual page 8

8 en | System introduction
Following types of faults are detected:
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Notice!
For the purpose of line monitoring the loudspeaker line isolator system generates DC‑voltage
i
on the entire loudspeaker line (including T‑Branches), therefore each loudspeaker on the line
has to be equipped in series with DC‑blocking capacitor. Loudspeakers without a capacitor
will be seen as a short‑circuit on the loudspeaker line.
Figure 3.2: Typical loudspeaker line isolator duty cycle
2021.07.28 | V1.00 |
Every short‑circuit on loudspeaker line immediately after it's occurrence with audio
recovery within 4 seconds,
open-loop fault on the main loop,
open of the T‑Branch (with EOL resistor enabled),
earth leakage on the main loop,
earth leakage of the T‑Branch (with EOL resistor enabled).
Installation manual
Loudspeaker line isolator system
Bosch Security Systems B.V.