Reduce
Installation Costs using Sigma II
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Sigma
II T series control panels can be used to make
considerable savings on some on installations
by connecting detectors, call points and sounders
to the same pair of wires on each zone thus
eliminating the need to install separate cables
for sounder circuits.
Estimates
show that in some instances, up to 40% can be
saved in time and materials!
The
Sigma II two-wire system works by reversing
the polarity of the detection lines when there
is a fire condition. This allows the sounders
to receive power from the control panel when
there is a fire alarm condition.
To
enable the control panel to continue to detect
fires on zones that are powering sounders, the
control panel reverses the zone polarity every
few seconds and if another detector or call
point has activated on one of these zones, a
fire condition will be detected.
This
method of wring allows each zone to have its
own sounder circuit as well as the two common,
dedicated sounder circuits that are fitted to
all Sigma II panels.
This
type of system has additional benefits in that
it has zonal sounder circuits that can be configured
to operate as follows:
| Common
alarm |
any fire condition operates all sounder
circuits. |
| Two
stage alarm |
the
two common sounder circuits and the zone
in alarm operate continuously and the
remaining zonal sounder circuits pulse,
1 second on/1second off. |
| Zonal
alarm |
only
the two common sounder circuits and the
zone in alarm operate. |
This flexibility makes Sigma II a suitable choice
for many types of installation including multi-occupancy
buildings that require evacuation only after
confirmation of a fire incident to prevent unwanted
disruption.
The
system can be used with two-wire detector bases
and detectors manufactured by both Hochiki and
Apollo and with any type of polarized sounder.
By using call points fitted with parallel 470R
and 680R resistors such as the WR2012 manufactured
by KAC, it is possible to differentiate between
call points and detectors allowing a delay to
be applied to the sounder outputs for a detector
alarm and instantaneous alarms from call points
or vice versa.
Sigma
II T series control panels are fully tested
and certified to EN54-2 and EN54-4 and carry
the prestigious BSI Kitemark which gives end
users extra peace of mind.
For
further technical information on Sigma II T
series control panel 
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