DURAG D-LX 200, Manual

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Design and Function
D − LX 200, D − LX 720
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4 Design and Function
This chapter explains the mode of operation of the Compact Flame Monitor
and the interaction of the components involved.
4.1 Functional description
The Compact Flame Monitor D − LX 200, D − LX 720 comprises an optical flame
sensor and a control unit in one housing. The flame sensor converts the light
signal of the flame into an electrical signal, while the control unit ensures self-
monitoring, evaluates the flame signal and communicates the result.
The operator must provide the necessary purge air to protect the optics from
dust and / or hot gases, and the power supply.
0/4 ... 20mA
Modbus
Optical out
D-LX 200
LX
20
0-
11
-001
Supply
24V 5W
Supply
Purge air
Boiler
Contact
Figure 4.1: System overview D − LX 200
D-LX 720
0/4 ... 20mA
Modbus
Optical out
Supply
24V 5W
Supply
Purge air
Boiler
Contact
Fibre optic
system
Figure 4.2: System overview D − LX 720
The flame monitor D − LX 200, D − LX 720 is available with semiconductor
photo-diodes for the band of radiation in the shortwave ultraviolet (UV) or
infrared range (IR).
The photo-diodes used in the flame sensor evaluate different spectral ranges
of the flame, depending on the version. The signal from the photo-diodes