DURAG D-LX 201 User Manual

8 | Flame monitor settings
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D-LX 201/721
As far as possible, adjust the flame monitor settings such that the flame monitor
shows 0 or 4 mA with flame OFF, and 20 mA with flame ON.
The flame monitor must always prevent the false simulation of a flame in all operating
statuses and in an extremely wide range of firing conditions.
If the optimal viewing position has been selected and the correct settings made for the
amplification characteristic and the switching thresholds, the flame monitor must
always reliably report a switched off burner or an impermissible impairment of a flame
display. The influence of any background radiation sources must not generate a
defective system status.
Flame monitor settings will usually have to be adjusted in the event of changes to the
combustion plant, the use of different fuels or new procedures (e.g. low load).
If the flame monitor no longer recognises the flame it is meant to be monitoring once it
has been set to insensitive to background radiation, then the difference between the
background radiation and the useful light (meaning the flame being monitored) is too
low.
1.
Check whether the position of the sighting tube and its alignment on the flame are
correct.
2.
Check whether the selection of a different amplification characteristic with or
without additional digital filtering possibly leads to better results.
When the D-LX 201 InformationCentre is used, the settings assistant decides whether
the amplification is better with or without additional digital filtering.
WARNING
If both range A
and
range B are being used, then the settings must be adjusted
separately for each range.
Note the information on range selection in section 8.1 Range selection [}72].
8.6 Flame Failure Detection Time (FFDT)
The
Flame Failure Detection Time (FFDT)
(formerly: safety time [}115]) is the time it
takes the flame monitor to respond to a flame failure or an impermissible impairment
of the combustion process. The relay contact for the flame ON signal is then deactiv-
ated.
The flame monitor has a standard FFDT of 1 second. Additional standard values
(2sec, 3 sec and 5 sec) are available on request. The FFDT specified on the type la-
bel must match the FFDT set for the device.
With the FM-approved versions D-LX *** ***-H*and D-LX *** ***-I*, the maximum
permissible Flame Failure Detection Time (FFDT) is 3 secs, i.e. the 5-sec setting must
not be used. The FM regulations stipulate a maximum FFDT of 4 secs.

DURAG D-LX 201 Specifications

General

Brand	DURAG
Model	D-LX 201
Category	Measuring Instruments
Language	English