Model FS17X
™
Fire and Flame Detector
INSTALLATION GUIDE and OPERATING MANUAL
Fire Sentry Corporation
Document No. 6178-007 - Rev. F
© Copyright 2012
All Rights Reserved
Page 11
SECTION 3: OPERATION
3.1
Principle of Operation
Fire Sentry Corporation’s (line of Multi-Spectral and MultiBand
™
Infrared Fire and Flame Detectors are
sophisticated, state of the art, electro-optical digital radiant energy Detectors 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.
Infrared (IR) consists of spectral wavelengths longer than the color Red. For the FS17X Detector, the IR
spectral range for fire detection, which a large portion of the spectrum is invisible to the human eye, is from
approximately 400 to 3000 nanometers (0.4 to 3.0 microns). Fire Sentry Corporation’s Detectors sense and
measure the radiant energy generated by a fire at the speed of light using high speed infrared quantum
sensors for its IR detectors.
Fire Sentry Corporation’s patented FSX Fire Detectors also use two additional spectral regions, the Visible
Band, that spans from about 400 to 700 nanometers (0.4 to 0.7 microns) and the NearBand IR that span from
about 0.7 to 1.1 microns. The Visible Band and NearBand IR are used primarily to further discriminate against
non-fire false alarm sources.
As with all Fire Sentry Corporation Detectors, the Model FS17X Detector senses radiant energy generated by
both hydrocarbon and 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 Corporation has developed and refined these complex proprietary and patented WideBand IR
algorithms since 1981. 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 Corporation’s FSX 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 converted to high resolution digital values 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 via the RS-485 FireBus
II
™
. If the microprocessors determine, based on internal testing
and “through-the-lens” testing, that the Detector is not operating correctly, it records the Fault data in flash
memory and activates the Fault outputs and the yellow status LED. The digital data in the Detector can be
accessed with a PC for later analysis and record keeping using Fire Sentry’s Windows
®
based PC software
and the FSIM USB Interface Unit.
