Fire Sentry FS24X QuadBand Triple IR Installation Manual And Operating Manual Download Page 15

Page: 15 / 28

Model FS24X

™

Fire and Flame Detectors

INSTALLATION GUIDE and OPERATING MANUAL

Fire Sentry Corporation

Document No. 6178-001 - Rev. Q

Page 12

SECTION 3: OPERATION

3.1

Principle of Operation

Fire  Sentry  Corporation’s  (FSC)  multi-spectrum  and  multi-spectral  infrared  Fire  and  Flame  Detectors  are
sophisticated,  state  of  the  art,  electro-optical  digital  radiant  energy  transducers  that  sense  the  wideband
radiant  energy  emitted  by  fire’s  combustion  processes  that  include  flames’  molecular  emissions  and  hot
particulate blackbody emissions.  Radiant Energy Fire Detectors respond much faster to flames and fires at a
longer  distance  than  other  types  of  conventional  photoelectric  and  ionization  smoke  and  heat  detectors
because  a  fire’s  emitted  radiant  energy  travels  at  the  speed  of  light.    Fast  response  is  critical  for  detecting
flaming fires in time to successfully activate suppression or activate other fire responses such as closing fire
doors.  Seconds can make the difference between suppressing a small fire with little or no damage or having
a disastrous fire that overwhelms a suppression system thereby failing to stop the fire.

Infrared (IR) consists of spectral wavelengths longer than the color red. The IR range for fire detection, which
is invisible to the human eye, is from about 700 nanometers to 7000 nanometers (0.7 to 7.0 microns). Fire
Sentry’s FS24X Fire Detectors utilize a NearBand IR

™

portion of the spectrum from approximately 0.7 to 1.1

microns and a WideBand IR portion from approximately 1.1 to 7.0 microns. This allows the FS24X Detectors
to sense over 80% of the total radiant “Blackbody Energy” emitted by a fire. Fire Sentry’s Detectors sense
and measure the radiant energy generated by a fire at the speed of light.

FSX Detectors also utilize  an additional spectral region, the Visible  Band, that spans from about 400 to 700
nanometers (0.4 to 0.7 microns.)  The Visible Band is used to further discriminate against non-fire false alarm
sources.  The Model FS24X Detectors also sense the specific WideBand 4.3 IR

™

“Triple IR”. Sensing these

hydrocarbon  wavelengths  does  not  inhibit  the  Detector’s  ability  to  see  non-hydrocarbon  fires.    Built-in
microprocessors  use  sophisticated  Digital  Signal  Processing  (DSP)  to  accurately  distinguish  radiant  energy
from a real fire and a false alarm source(s).  Fire Sentry has developed and refined these complex proprietary
and  patented WideBand IR algorithms over the last  30  years.  These  patented  algorithms perform real-time
DSP, and precisely analyze the signals in high-resolution frequency and time domains.  This decision making
process involves thousands of real-time calculations every second.  Fire Sentry  FS24X Detectors use solid-
state  high  speed  quantum  sensors  (not  heat sensors  such  as  pyroelectric  or  thermopile)  that  all  respond  to
the  fire’s  radiant  energy  emissions.    The  quantum  sensors  convert  the  rate  of  photonic  energy  directly  into
analog electrical signals.  These analog signals are  then converted to high resolution digital bits for real-time
microprocessor  analysis.    The  Detector  microprocessors  incorporate  random  access  memory  (RAM),  read-
only  memory  (ROM),  and  non-volatile  flash  memory.    When  the  microprocessors  determine  that  a  real  fire
has  been  detected,  the  pre-alarm  digital  sensor  data  (FirePic

™

) and the event information are recorded in

flash memory. Depending on the configuration, other actions may include activating one or more status
LEDs, relays, a current loop and sending digital data such as the RS-485 FireBus

, and ModBus. If the

micro

processors determine, based on internal testing and “through-the-lens” testing, that the Detector is not

operating correctly, it records the Fault data and activates the Fault outputs and the yellow status LED. The
digital data in the Detector can be easily accessed with a PC for later analysis and record keeping using Fire
Sentry’s Windows

based PC software and FSIM-2 USB Interface Unit.

3.2

Configuring the Detector

IMPORTANT

: Changing the Detector Settings

– To activate changes to the settings using SW1, SW2 and

SW3, reset the Detector by removing and re-applying 24 VDC input power.

The Digital Address for the RS485 Communication can be set using positions 4 through 10 on SW1. Switch
positions 1, 2 & 3 for SW1 are for factory use only and should not be changed.