DURAG D-LX 200, Руководство пользователя

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Design and Function
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D − LX 200, D − LX 720
passes through a two-channel (Chan. 1 and Chan. 2) microcontroller-
adjustable amplifier with filter stages. Both the static and the dynamic portion
of the flame radiation are available for evaluation at the output. The range
selection enables switching of the flame monitor settings to another parameter
set (intensity and frequency switching threshold, current gain characteristic).
D-LX 200
D-LX 720
IR/UV
MC 1
MC 2
MC 3
LX
200_001_
B
lock
_
00
1
Analog 1
Analog 2
Chan nel 2
Chan nel 1
Modbus
LED
optical out
0/4.....20 mA
ready for
operation
flame on
Figure 4.3: Block diagram
In both microcontrollers for control and monitoring of the safety-relevant flame
monitor functions and self-monitoring, both the static and the dynamic flame
signals, depending on the set switching threshold (frequency, intensity), are
evaluated for the Flame ON or Flame OFF signal.
Two relay contacts connected in series and a green LED in the front panel are
available for the flame signal. The intensity of the flame signal can also be
displayed using a field bus, an optical data bus and a 0/4 .. 20mA current
output.
Readiness for operation or malfunction is indicated by a contact of the
dynamically controlled fault relay, with monitoring of the internal operating
voltages and all safety-relevant hardware functions, and LEDs in the front
panel.
A single-channel microcontroller controls the non-safety relevant input and
output functions.
The internal power unit transforms electrically isolated from 24V to 12V/3.3V.
4.1.1 Ultraviolet flame sensor
The UV radiation zone of a flame is generally much smaller than the IR zone.
In addition, internal components or boiler walls do not emit any dynamic
UV radiation. UV flame monitors are therefore very selective, i.e. insensitive to
background radiation.
In the D − LX 200 UA, D − LX 720 UA a photo-diode with a spectral sensitivity of

= 190 nm to 520 nm is used. The integrated flame sensor therefore records
the dynamic blue to transparent band of radiation, e.g. of gas, oil and coal
flames, without suffering significant signal interruptions due to water vapour,
recirculation gas or similar UV-absorbing gases.
In the D − LX 200 UAF, D − LX 720 UAF the photo-diode of the D − LX 200 UA,
D − LX 720 UA is used, with an optical filter. The filtering results in a limited