260  AO2000 CONTINUOUS GAS ANALYZERS  |  OI/AO2000-EN REV. B 
 
 
 
Magnos27: Substitute gas calibration 
Example 
Substitute gas calibration of the Magnos27 analyzer module is described 
using the example of "Oxygen measurement in flue gas". 
Oxygen measurement in flue gas 
The sample gas composition is known in the case of oxygen measurements. 
Test gases 
Zero gas: 16 vol.% CO
2
 in N
2
 
Span gas: 10 vol.% of O
2
 and 8.3 vol.% of CO
2
 in N
2
 
Calibration with substitute gas 
Since these test gases are not available everywhere, the analyzer module is 
factory-set for calibration with a substitute gas. 
In this case an additional measurement range is calibrated for 0 to 25 vol.% 
of O
2
 in N
2
 (N
2
 and O
2
/N
2
 mixtures are available practically everywhere). 
Measuring ranges 
 
Component 1  O
2
 in flue gas  Meas. range 1  0 to 5 vol.% 
        Meas. range 2  0 to 10 vol.% 
Component 2  O
2
 in N
2
 (substitute gas)  Meas. range 1  0 to 25 vol.% 
Calibration parameters 
 
Calibration method  Substitute gas calibration 
Zero component  Component 2  Meas. range 1 
Span component  Component 2  Meas. range 1 
Calibration 
•  Calibrate zero with N
2
 (component 2). 
•  Calibrate span with dried air (contains 20.96 vol.% of O
2
) or with an 
O
2
/N
2
 mixture. 
Other measurement tasks 
For other measurement tasks select the test gases and measurement ranges 
in a similar manner according to the sample gas composition.