264  AO2000 CONTINUOUS GAS ANALYZERS  |  OI/AO2000-EN REV. B 
 
 
 
Oxygen sensor: Notes for calibrating 
Test gases 
The zero point of the oxygen sensor is not calibrated, as it is stable owing to 
the principle. 
Ambient (non-process) air with a constant oxygen content (e.g. 20.96 vol.%) 
is required for span calibration. Synthetic air can also be used. 
Test gases for simultaneous calibration of the oxygen sensor and analyzer 
module 
The oxygen sensor and associated analyzer module are calibrated simulta-
neously. 
Therefore when the oxygen sensor is to be calibrated with the following 
analyzer 
•  Magnos206 and Magnos28 with single-point calibration 
•  Limas11 IR, Limas21 UV, Limas21 HW with calibration cells 
•  Uras26 with calibration cells 
the zero gas should contain the required concentration of oxygen. 
In all other cases the span gas should contain the required concentration of 
oxygen. 
External control arrangement 
The design of the external control of calibration should take into considera-
tion that the oxygen sensor’s span value is stable only after a waiting period 
of ≥ 40 seconds. 
Wait until the warm-up phase has ended 
The oxygen sensor is always calibrated at the same time as the associated 
analyzer module. Therefore, calibration should begin only after this module’s 
warm-up phase.