8-C-8
Chapter 8: Gas Analyzer Calibration
42/24-10 EN Rev. 9
Magnos206: Single-Point Calibration
Single-Point
Calibration
The long-term sensitivity drift of the Magnos206 analyzer module is less than
0.05 Vol.-% O
2
per year for measurement ranges up to 25 Vol.-% O
2
. Thus a
regular offset correction is sufficient. This so-called single-point calibration can be
conducted at each point on the characteristic curve since a parallel shift of this
curve results. Depending on the measurement task involved, we recommend
performing an additional span calibration once a year.
Note: The short-term sensitivity drift can amount to 1% of the measured value per
week.
Test Gas
A test gas with any concentration of O
2
can be used for single point calibration as
long as it lies within one of the measurement ranges in the analyzer module.
Environmental air can also be used as the test gas.
The test gas must have the same moisture content as the process gas.
CAUTION!
In order to avoid accumulations of explosive gas mixtures, do not use air as
a test gas for single-point calibration when measuring combustible gases.
Suppressed
Measurement Ranges
Single point calibration can also be done within a suppressed measurement range
if the suppression ratio is
≤
1: 5. In this case as well, the O
2
concentration of the
test gas must lie within the measurement range.
Air Pressure
In single point calibration, the current air pressure must be taken into account.
This is done automatically if a pressure sensor is incorporated in the analyzer
module.
Note: The sensitivity drift is
≫
0.05 Vol.-% O
2
without pressure correction.
Calibration Method
When the analyzer module has one sample component the single-point calibration
is carried out as common calibration only at the zero point.
When the analyzer module has more than one sample component the single-point
calibration is carried out as an substitute gas calibration only at the zero point.
For detailed information on the calibration methods, see the “Calibration
Methods” section, page 8-A-10.
Continued on next page
