Siemens ULTRAMAT 23 Series Equipment Manual page 165

Calibration of the measured value drift
The deflection signal of the sensor is subject to drift. This drift can be detected only through
regular review and corrected as needed. This involves using a calibration gas with a defined
concentration of hydrogen sulfide.
To keep potential measurement uncertainty within strict limits, we recommend a monthly
calibration with a calibration gas with a concentration of 50 vpm H
ULTRAMAT 23
Equipment Manual, 04/2022, A5E37100388-012
Application note
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