Siemens SIPROCESS GA700 - Page 132

Accompanying gas (concentration 100vol.%) Zero point deviation in
vol.%O
2
absolute
Water H
2
O -0.03
Hydrogen H
2
+0.26
Since the zero point deviations are linear, it is easy to convert to lower interfering gas
concentrations.
In the case of interfering gases with a constant concentration, an interfering gas correction
with constant zero point o󹪜set can be carried out in the gas to be measured. If the
concentration of the accompanying gases changes during the oxygen measurement, a
variable interfering gas correction has to be carried out. An external concentration must
be determined for each interfering gas with a considerable zero point deviation. Its result is
fed as interfering gas concentration into the OXYMAT7 analyzer module and the correction
value is calculated constantly.
Information on interference gas correction is available in the following operating manuals:
• Operating with the Local User Interface Table A-2 References1-Operating ManualsLUI
(Page179)
• Operation with SIMATIC PDM Table A-3 References2-Operating ManualsPDM (Page179)
See also
References (Page179)
9.5.2 CALOMAT 7
Overview
To determine the cross-interferences of accompanying gases with several interference gas
components, you must know the sample gas composition. The following table contains the zero
o󹪜sets for the carrier gas N
2
as H
2
equivalent values with 10% interference gas
Table 9-6 Zero o󹪜set in the system H
2
in N
2
Interference gas H
2
equivalent values with 10% inference gas
CH
4
1.77%
C
2
H
6
0.47%
C
3
H
8
-0.28%
CO -0.10%
CO
2
-0.84%
O
2
0.19%
N
2
O -0.83%
NH
3
1.45%
Ar -1.22%
He 6.32%
SF
6
-2.15%
Commissioning
9.5Zero point error
Wall-mounted device
132 Operating Instructions, 07/2023, A5E31930403-AB