General Monitors FL3101H, Руководство пользователя

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Models FL3100H/3101H
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RS-485 Modbus RTU output
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Optional: HART communication
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Optional: Redundant RS-485 Modbus RTU output
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Figure 23: Spectral Response of UV and IR Detectors
(See Sections 3.0 and 5.2 for more information on detector outputs.)
10.2.2 UV/IR Flame Detector - FL3100H
The Model FL3100H is a discriminating UV/IR Detector, which makes use of an ultraviolet
radiation sensitive phototube in addition to an infrared detector. This combination provides a
flame detector which is highly immune to false alarms.
The UV portion of the detector, as described in the previous section, is combined with an
infrared detector, which responds to changes in the intensity of infrared radiation. By sensing
very specific wavelengths in both the UV and IR spectra (Figure 23) and then processing these
signals with a microcomputer, a very high degree of discrimination is achieved.
Incorporated in the IR circuitry is a flicker discrimination circuit. This permits the detector to
ignore steady IR sources such as hot objects. The inherent flickering of a flame provides the
necessary modulation to activate the IR circuit.
Since a flame is a copious source of both ultraviolet and infrared radiation, discrimination is
provided when both UV and IR emissions are detected. If only UV is detected, as in the case of
arc welding, no alarm is given. If only IR is detected, such as a large modulating hot object, no
alarm is given. However, if both conditions are met in the correct combination and intensity, as
determined by an algorithm in the microcomputer, a fire is identified and the alarm outputs are
activated.