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In general the following formula is applicable:
Fig. 88: Formula to calculate the effects of coexisting gases
The adjusted concentration values of the gas mixture components have the following
values:
C2H6
- 0.0043 vol%
(Ethane)
CO2
- 0.080 vol%
N2
0.0000 vol%
The value of the sum of the cross-sensitivities is -0.1123 vol%. This value is needed to adjust
the zero point. The zero point needs to be set to +0.1123 vol%.
As you see here, the cross-sensitivity is not negligible. If you don't consider the effects of
coexisting gases, it could mean an approximately 2% relative error for the whole
measurement.
The following table shows the cross-sensitivity of the most important gases at +20 °C
(+68 °F) and +50 °C (+122 °F).
The cross-sensitivity values from the table are referring to 100 vol% of
Note
the corresponding gas at +20 °C (+68 °F) and +50 °C (+122 °F).
All values are corresponding to a zero point calibration of 100 vol% N
calibration of 100 vol% O
2
Gas
Chemical formula
Argon
Ar
Acetylene
C
2
Acetone
C
3
Acetaldehyde
C
2
Ammonia
NH
Benzene
C
6
Bromine
Br
2
Butadiene
C
4
Methyl propene
C
4
n-Butane
C
4
Chlorine
Cl
2
Hydrogen chloride
HCL
77
PMA1000/PMA1000L | 1.00.00
.
Cross-sensitivity values
+ 20 °C (+68 °F)
- 0.23
H
- 0.26
2
H
O
- 0.63
6
H
O
- 0.31
4
- 0.17
3
H
- 1.24
6
- 1.78
H
- 0.85
6
H
- 0.94
8
H
- 1.10
10
- 0.83
- 0.31
, and a limit point
2
+50 °C (+122 °F)
- 0.25
- 0.28
- 0.69
- 0.34
- 0.19
- 1.34
- 1.97
- 0.93
- 1.06
- 1.22
- 0.91
- 0.34
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