AO2000 CONTINUOUS GAS ANALYZERS | OI/AO2000-EN REV. B 235
Caldos27: Single-point calibration with standard gas
Single-point calibration with standard gas
For measuring ranges ≥ class 1 in the Caldos27 analyzer module, a sin-
gle-point calibration can be carried out with standard gas (standard gas
calibration). This standard gas calibration is carried out exclusively as span
calibration and causes an amplification correction. Safety-related measure-
ments are excluded from this technique. Depending on the measurement
task involved, the zero and end points should be verified periodically (rec-
ommendation: once a year).
Note: Classification of measuring ranges into class 1 and class 2 is specified in
"Advance Optima AO2000 Series Continuous gas analyzers" data sheet.
Measurement range for standard gas
When the Caldos27 analyzer module is ordered with standard gas calibra-
tion, the factory-set measurement range for the standard gas is
0 to 60,000 rTC (rTC = relative thermal conductivity). During basic calibra-
tion in the factory one standard gas is calibrated in this measurement range.
Due to sensor tolerances the values of other standard gases can differ by up
to 5 % from this scaling.
Set points for standard gases
N
2
10,000 rTC
Air 10,070 rTC
Ar 7,200 rTC
CO
2
7,500 rTC
CH
4
14,000 rTC
He 50,000 rTC
H
2
60,000 rTC
Calibration method
Standard gas calibration is fundamentally a substitute gas calibration (see
page 223) without zero calibration. The correction values are transferred to
all the analyzer module’s sample components and measurement ranges.