Stratos Multi E401N
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6.6 Process Variable Oxygen Calibration/Adjustment
Note:
During calibration, the function check (HOLD) operating state is active for each of the calibrated
measuring channels. The outputs respond as configured.
• Calibration: Detect deviations without readjustment of calibration data
• Adjustment: Detect deviations with readjustment of calibration data
NOTICE!
When using analog sensors, adjustment is required following sensor replacement.
Oxygen Calibration/Adjustment Explanations
Every oxygen sensor has an individual slope and an individual zero point. Both values change, for ex-
ample, as a result of aging and wear. For a sufficiently accurate oxygen measurement, the sensor data
should be regularly adjusted.
If the electrolyte, the membrane body (the membrane cap), or both are replaced during maintenance
of amperometric sensors, this change must be confirmed manually in the Maintenance menu:
Maintenance
[I] [II] … Oxy
Membrane Body Replacement
Maintenance Functions for Oxygen Sensors, p. 134
Calibration is required after each membrane body replacement. This entry impacts on the accuracy of
the calibration.
Recommendations for Calibration
For best performance, you should always calibrate in air. Compared to water, air is a calibration
medium which is easy to handle, stable, and thus safe. In the most cases, however, the sensor must be
removed for a calibration in air. In certain processes the sensor cannot be removed for calibration.
Here, calibration must be performed directly in the process medium (e.g. with aeration).
For applications where concentration is measured, calibration in air has proved to be useful.
Common Combination: Process Variable/Calibration Mode
Measurement
Calibration
Saturation
Water
Concentration
Air
If there is a temperature difference between the calibration and the measured media, keep the sensor
in the respective medium for an equalization period before and after calibration in order to obtain
stable measured values.
The type of calibration pressure detection is preset during parameter setting:
Parameter Setting
[I] [II] ... Oxy
Pressure Correction
Note:
Amperometric sensors must be sufficiently polarized prior to calibration/adjustment. Follow the
information on the sensor in the sensor user manual to ensure that the calibration is neither falsified
nor unstable.