Flame Supervision With Ionization Probe; Measuring Circuit - Siemens LME SERIES Installation Manuals

Technical data (cont´d)
Flame supervision
with ionization probe
Detector voltage between ionization probe and ground
(AC voltmeter Ri ≥ 10 MΩ)
Switching threshold (limit values):
Switching on (flame on) (DC ammeter Ri ≤ 5 kΩ)
Switching off (flame off) (DC ammeter Ri ≤ 5 kΩ)
Detector current required for reliable operation
Switching threshold in the event of poor flame during operation
(LED flashes green)
Short-circuit current between ionization probe and ground
(AC ammeter Ri ≤ 5 kΩ)
Note

Measuring circuit

10/25
Building Technologies
HVAC Products
¹) For applications outside the European Community, operation at mains voltage
AC 120 V / AC 230 V ±10% is
With the same quality of flame, the detector current with the LME... may be other
than with the LMG... / LGB...
Flame supervision with ionization is accomplished by making use of the conductivity
and rectifying effect of the flame. The flame signal amplifier only responds to the DC
current component of the flame signal. A short-circuit between ionization probe and
ground causes the burner to initiate lockout.
M
+
+
LME...
1
C
7101v01/0804
For detector currents, refer to « Technical data ».
UN = AC 120 V ¹)
AC 50...120 V
≥ DC 1.5µA
≤ DC 0.5µA
≥ DC 3µA
Approx. DC 5µA
Max. AC 50...150µA
ensured
Legend
-
C Electrolytic capacitor 100...470µF; DC 10...25 V
ION Ionization probe
M Microammeter, Ri max. 5000Ω
ION
At mains voltage
UN = AC 230 V ¹)
AC 115...230 V
≥ DC 1.5µA
≤ DC 0.5µA
≥ DC 3µA
Approx. DC 5µA
Max. AC 100...300µA
CC1N7101en
27.11.2008