DURAG D-LX 200, Manual

Page: 64 / 116

Adjusting the Flame Monitor
64
D − LX 200, D − LX 720
As far as possible, make the settings on the flame monitor so that the monitor
indicates 0 or 4 mA for Flame OFF and 20 mA for Flame ON.
The flame monitor must prevent simulation of a flame in all operating states
and under the most diverse combustion conditions.
With optimal adjustment of the viewing position, the gain characteristic curve
and the thresholds of the flame monitor, the D
− LX 200, D − LX 720 must always
reliably indicate a switched-off burner or an unacceptable deterioration in the
flame pattern. The influence of background radiation sources must not be
allowed to generate a defective system state.
If, after setting the flame monitor to be insensitive to background radiation, the
monitor can no longer detect its own flame, the difference between
background radiation and useful light (flame to be monitored) is too small. In
this case, it is advisable to switch the gain characteristic curve one "gain
characteristic curve higher" with the MODE (DIP) switches. The steeper
characteristic curve enables a greater signal difference between background
radiation and useful light.
If Range A and Range B are used, the settings for each range must be made
separately!
Please also note the information for the Range selection from page 59.
6.6 Safety time
The safety time is the response time of the flame monitor to an outage of the
flame signal (digital signal from the (
 ) flame radiation and the resulting
switch-off of the relay contact for the Flame ON signal).
The Compact Flame Monitor D − LX 200, D − LX 720 has a default safety time of
1 second. Further default values (2 s, 3 s and 5 s) are available on request.
The safety time noted on the type plate must match the safety time set on the
device.
Burner controls and flame monitors are type-approved devices.
Any
interventions or modifications will result in loss of the approval.
Repairs may
therefore only be carried out by the manufacturer or his representatives.
The adjustment of flame monitors should also only be performed by
appropriately trained personnel, in the interest of safety.
DURAG offers suitable training for this purpose.
Particular care must be taken not to change switch positions 1 and 2 (see
Figure 6.6 and Table 6.1 on page 58) when setting the gain characteristic
curves at DIP switches S3 and S4. The switch position corresponding to the
safety time noted on the type plate can be verified in Table 6.2.