DURAG D-LX 200, Manual

Page: 57 / 116

Adjusting the Flame Monitor
6.2 Setting the gain characteristic curve
A characteristic feature of the D − LX 200, D − LX 720 is the automatic
adaptation of the internal gain to the signal strength of the flame. The
sensitivity of the gain adaptation can be precisely matched to the relevant
combustion process (by preselecting the correct gain characteristic curve).
MODE switches S3 and S4 (both on printed circuit board no.2) enable
preselection of 8 different gain characteristic curves (Figure 6.5: V1-V8) for
different combustion conditions. The steeper the selected gain characteristic
curve, the higher the input gain of the flame monitor and the more sensitive the
reaction to the flame radiation.
If gain characteristic curve V8 is selected, even a small flame radiation can
result in exceeding of the threshold (intensity) and thus trigger a Flame ON
signal.
Flammensignal
Intens
ität D-LX 200, D
-LX 7
20
Flamesignal
Intens
ity D-LX 20
0, D-LX 72
0
Figure 6.5: Gain characteristic curves
Gain characteristic curve V8 has the largest and V1 the smallest input gain.
D − LX 200, D − LX 720
57