Siemens LMV 5 Series, Technical Instructions, Page: 200 / 374

Technical Instructions LMV Series
Document No. LV5 ‐ 1000
Section 6 Page 28 SCC Inc.
As previously mentioned, the QGO20 is only capable of measuring %O
2
wet. This is true since it is an in ‐
situ oxygen sensor, not needing any type of water trap, desiccant, or filter. In ‐ situ sensors typically have
a much shorter delay time (Tau time) and require much less maintenance than other types of O
2
sensors.
Most hand ‐ held combustion analyzers measure %O
2
dry, and therefore will be considerably different
from the %O
2
wet measured by the QGO20 sensor.
Figure 6 ‐ 11 shows these approximate differences along with the raw milli ‐ volt signal from the Zirconium
oxide O
2
cell. As one would expect, the raw milli ‐ volt signal varies with sensor temperature, but this
variance is compensated by the PLL52 module so the LMV52 is fed an accurate, compensated O
2
value.
%O
2
Wet
%O
2
Dry
(Natural Gas)
Output Voltage
(mV) @ 1292 F
Output Voltage
(mV) @ 1320 F
0.1 0.1 111.79 113.59
1 1.3 63.61 64.63
1.5 1.9 55.12 56.01
2 2.5 49.10 49.90
2.5 3.1 44.43 45.15
3 3.8 40.62 41.27
3.5 4.4 37.39 38.00
4 5.0 34.60 35.16
4.5 5.6 32.13 32.65
5 6.3 29.93 30.41
5.5 6.9 27.93 28.39
6 7.5 26.11 26.54
6.5 8.1 24.44 24.83
7 8.7 22.89 23.26
7.5 9.3 21.44 21.79
8 9.9 20.09 20.42
8.5 10.6 18.83 19.13
9 11.2 17.63 17.91
10 15.43 15.67
11 13.43 13.65
12 11.61 11.80
13 9.94 10.10
14 8.38 8.52
15 6.94 7.05
16 5.59 5.68
17 4.32 4.39
18 3.13 3.18
19 1.99 2.03
20 0.92 0.94
20.9 0.00 0.00
Figure 6 ‐ 11: O
2
Wet, O
2
Dry, and Nernst Voltage Conversion (approximate)
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