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Plena Voice Alarm System
| Basic System Manual | Configuration
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4.5.4
Message supervision
If supervision is enabled (see section 4.5.1), the internal
message manager of the voice alarm controller is
supervised. This message supervision consists of
supervision of the wave player using a check-sum and
supervision of the audio path using a pilot tone.
4.5.5
Line supervision
4.5.5.1
Introduction
If supervision is enabled (see section 4.5.1), all
loudspeaker lines are supervised. Line supervision
consists of:
•
Short-circuit supervision (see section 4.5.5.2).
•
Impedance supervision (see section 4.5.5.3).
•
Short-to-ground supervision (see section 4.5.5.4).
4.5.5.2
Short-circuit supervision
The voice alarm controller continuously monitors all
loudspeaker lines in the system for short-circuits. If a
short-circuit is detected, the line output of the
short-circuited line is isolated and shut down within 200
ms. The system will remain operational. If the line is
dual-redundant connected (
A
and
B
) the short-circuited
line remains operational as well.
4.5.5.3
Impedance supervision
If supervision is enabled, the voice alarm controller
measures the impedance of all loudspeaker lines once
every 90 seconds. The reference values for impedance
supervision are stored in the voice alarm controller
during the system calibration (see section 5.3). If a
difference of > 15% is detected between the measured
line impedance and its reference value, the line is
considered faulty.
4.5.5.4
Short-to-ground supervision
If supervision is enabled, the voice alarm controller
continuously monitors all loudspeaker lines in the
system for short-to-ground situations. If a leakage
current > 30 + 15 mA is detected in a line, the line is
considered faulty.
4.5.6
Emergency microphone
If supervision is enabled (see section 4.5.1), the
audio
path and the PTT switch of the emergency microphone
are monitored from the capsule to the connection with
the voice alarm controller.
4.5.7
Mains power supervision
If supervision is enabled (see section 4.5.1), the
availability of the mains power is supervised.
4.5.8
Battery supervision
If supervision is enabled (see section 4.5.1), the
availability of the back-up power is supervised.
4.5.9
Internal power amplifier
supervision
If supervision is enabled, the internal power amplifier of
the voice alarm controller is supervised. The function of
this power amplifier depends on the position of the
2ch
operation
switch (see section 4.5.11).
4.5.10 External power amplifier
supervision
If supervision is enabled and the
2ch operation
switch
(see section 4.5.11) is in the
ON
position, the external
power amplifier is supervised. In 2-channel mode, the
external power amplifier is always the call power
amplifier.
Note
For a correct impedance supervision, connect
loudspeakers as described in section 3.10.
table 4.3: Internal power amplifier functions
Operational mode
Function
1-channel
BGM/Call power amplifier
2-channel
BGM/Spare power amplifier
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