4 ©Firey AB (Oktober 2016)
Theory of operation
The Model 860 ame detectors
The Model 860 ame detectors are multi-spectrum detectors, which
provide a high degree of discrimination by sensing widely separated
ame emission spectra, both of which are found in hydrocarbon
and certain specied non-hydrocarbon res. Sophisticated signal
processing is accomplished by microprocessor technology. Automatic
self-testing of the electronics, sensors and optical surfaces is
accomplished using light guides. The light guides direct radiant energy
by a calibrated internal source lamp to the sensors, whereby it can be
determined if the detector’s windows have been contaminated to the
point that would render it blind to res. This self-interrogation is done
a minimum of four times per hour, thus providing the ultimate in re
detection reliability.
The two spectral regions selected for sensing re signals are the
Ultraviolet (UV) and Infrared (IR). The UV sensor is the stable, highly
reliable UV photon sensor tube which has a peak response centered
around 0.22 microns. The design of the tube is optimized for the
highest sensitivity to the UV radiation emitted by a ame with the
lowest response to background radiation such as near UV, black light,
visible light, sunlight and blackbody radiation, thereby providing a
very high signal-to-noise ratio.
The IR sensor is responsive to 4.4 microns. This Spectral frequency
is always present in a hydrocarbon re due to the excitation of hot
carbon dioxide molecules.
Additionally the option is available in which the IR sensor is responsive
to 2.9 microns as well as 4.4 microns. This option enables the detector
to sense certain non-hydrocarbon res. The detector’s autonull feature
eliminates interference due to background radiation in these regions
of the spectrum.
The Model 860 ame detector not only requires the coexistence of
UV and IR radiation, but also their presence in specic ratios. The ratio
must conform to the radiation pattern of specic res (see Figure 3).
This patented Fire Event Analysis (FEA) ensures the highest possible
discrimination between re and non-re sources.
The Model 660 ame detectors
The Model 660 ame detectors are single spectrum detectors utilizing
the same ultraviolet sensor tube as described for the Model 860 ame
detector.
The Model 660 ame detector requires only that a signal within the
detection envelope of the UV sensor will be present in a pre-dened
strength for a specied time duration. These parameters are user
adjustable and will determine the sensitivity and response time to all
res.
NOTE: Reference Figure 3 for appropriate sensor wavelength regions
to be used in Zeta calculation per NFPA 72 edition 2002 or later.
(Fig 3) typical hydrocarbon re spectrum
Specications
Environmental (All Models)
• Suitable for use in hazardous locations:
Class I, Division 1, Groups B, C & D
Class II, Division 1, Groups E, F & G
Type 4X rated.
• European Rating -
ll 2 G/D
Exd llB + H2 T5 Gb for gas (Industrial)
Ex tb IIIC T100°C Db IP66 for dust
Exd llB + H
2
T4 Gb for gas (High-Temp)
Ex tb IIIC T135°C Db IP66 for dust
Electrical Interface
• Nominal voltage input —24VDC (20 Min/32 Max).
• Maximum allowable ripple voltage — 240mV
• Current Draw (@ 24 VDC):
Model Standby Alarm Manual
Test
Auto
Test
860/660-XX0XX 90 mA 110 mA n/a n/a
860/660-XX1XX 90 mA 110 mA 250 mA 250 mA
• Relay Contact rating (860/660 Industrial Models) 2 Amps @ 30 VDC
(Resistive)
Relay Contact rating (660 High Temperature Model) 4 Amps @ 30
VDC (Resistive)
Note: Each detector contains two relays: (1) Fire, (1) Fault
• Current Loop Output (0 to 20 mA) - Industrial Temperature Models
Only (see Table 2)
• RS485 Half-duplex, Addressable, User Interface Baud Rate 9600 bits
per second
1 start bit, 8 data bits and 1 stop bit
• Power consumption (@ 24 VDC)
Model Standby Alarm Manual
Test
Auto
Test
860/660-XX0XX
2.16 W 2.64 W n/a n/a
860/660-XX1XX
2.16 W 2.64 W 6 W 6 W
DMLieferant Тел.: +7 (499) 990-05-50; +7 (800) 775-29-59 dmliefer.ru
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