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Technical Data (cont´d)
Flame supervision with
ionization probe
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No-load voltage at ION terminal
(X10–05 pin 2)
Caution!
The ionization probe must be protected against electric shock hazard
(electric shock hazard)!
Short-circuit current
Required detector current
Possible detector current
Max. perm. length of detector cable
(laid separately)
Warning!
Simultaneous operation of QRA and ionization probe is not permitted!
Note
The higher the detector cable's capacitance (cable length), the more voltage at the
ionization probe, and thus the detector current, drops. Long cable lengths plus very
highly resistive flames might necessitate low-capacitance detector cables (e.g. ignition
cable). In spite of technical measures taken in the circuitry aimed at compensating
potential adverse effects of the ignition spark on the ionization current, it must be
made certain that the minimum detector current required will already be reached
during the ignition phase. If this is not the case, the connections on the primary side of
the ignition transformer must be changed and / or the electrodes relocated.
Threshold values when flame is supervised by an ionization probe:
- Start prevention (extraneous light)
- Operation
Approx. U
Mains
Max. AC 1 mA
Min. DC 2.3 µA,
flame display approx. 30 %
When the more sensitive flame
supervision is activated, the required
detector current is halved (refer to chapter
Flame detection sensitivity in the Basic
Documentation P7544).
Max. DC 12...30 µA, flame display
approx. 100 %
3 m (wire–ground 100 pF/m)
Flame intensity (parameter 954) ≥18 %
Flame intensity (parameter 954) >24 %
21/30
CC1N7544en
21.05.2021
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