Planning and Installation manual VV600/VV602Plus
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3.1.4. The explosion channel
The explosion channel is set to detect very high amplitude and short duration
signals as caused by explosives. An alarm will immediately be triggered by the level
detector when the pre-set amplitude is detected. The sensitivity is pre-set and is not
affected by the sensitivity setting of the integration channel.
3.1.5. Power supply
The supply voltage is first filtered and regulated thus providing insensitivity to
electrical interference. The internal voltage requirement is 6 V thus allowing the
detector to operate in a broad voltage range. The power supply features extremely
good protection against high energy electrical surges. The transient absorbers and
the general design of the detector also give a very good protection against RFI, for
example from GSM cellphones.
3.1.6. Sabotage protection
Of course, the VV600Plus seismic detector is equipped with comprehensive anti-
tamper provisions, a tamper alarm is given when an attempt is made to:
•
Pry the unit off the wall
•
Burn or weld the unit
•
Lower the supply voltage below 7,5 V
•
Open the unit
The detector is equipped with a solid state relay and consequently no protection
against outside magnetic fields is necessary.
3.1.7. Alarm-output circuitry
The circuitry may be activated by all three detection channels. The alarm output
provides two forms of alarm signals:
•
One potential free normally closed contact, opening in alarm.
•
One open collector transistor output, going out of conductive mode upon
alarm condition.
The transistor is being protected against short circuit with a series resistor.
