D-LX 100
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3
3. Functional Description
The photo elements used in the integrated optical flame scanner evaluate different spectral ranges of
the flame. Those scanners with semiconductor photo elements cover ranges from short-wave UV-A
to infrared. The signal from the photo element passes through an amplifier with suppression of any
constant (non-dynamic) emitted energy. This amplifier can be set to one of two different levels. After
the amplifier, the signal runs through a high-pass filter and a pulse generation stage.
DURAG also offers a D-LX 100 flame scanner employing a UV photocell, which can monitor flames in
the UV-C range, where wavelength is very short. In this range it is unnecessary to suppress any non-
dynamic flame energy. This makes it possible to evaluate the often very high portion of constant
energy generated by the flame. Due to the way the photocell operates, it is unnecessary to equipped
this integrated flame scanner with an amplifier, high-pass filter or pulse generation stage. The cell
itself generates pulses using the voltage supply via an RC reset circuit.
The pulses generated by the integrated flame scanners, which offer a measure of the flame intensity,
are transmitted to the microprocessor system and will trigger a flame ON or OFF signal, depending on
the flame recognition threshold programmed in.
Three features are available for the flame signal: 1) a fail-safe relay contact, K2, 2) a green LED on
the front panel, and 3) a current output for display of the flame intensity. The current output is set at
the factory to either 4-20 or 0-20 mA.
Both operational readiness and fault status are signaled via a contact in the K1 fault relay, and either a
yellow (ready) or red (fault) LED on the front panel.
The DURAG D-ZS 087-20 Display Unit may be plugged into the jack on the front panel. This device
displays the flame intensity as a pulse signal between 0 and 4095 pulses/sec. and further aides in
setting the proper flame recognition threshold.
D-LX 100
9
0
9
0
D-ZS 087
D-ZS 087
D-ZS 087- 20
Reset
Mode
V2
V1
Gain selection (covered by housing)
Status display
Digital Display D-ZS 087-20
(only for setup)
Reset button
Connection for D-ZS 087-20
Flame threshold adjustment
(Fig. 2)
D-LX 100 with D-ZS 087
