Endress+Hauser Memosens COS51E, Operating Instructions Manual

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Memosens COS51E Commissioning
Hauser 25
4. NOTICE
Incorrect measurements caused by atmospheric influences!
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Protect the sensor against external influences such as sunlight and wind.
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Prior to calibration, adjust the atmospheric pressure if it does not match the
process pressure.
After 20 minutes, measure the oxygen saturation index in air.
5. Decide using the results:
a) Measured value is not 102 ± 2 %SAT → Calibrate sensor (adjust if necessary).
b) If the values are within the specified interval, the sensor does not need to be calibrated.
The time period between inspections can be extended.
6. Repeat the steps specified after two, four or eight months to determine the optimum
calibration interval for your sensor.
7.3.3 Calibration in air with 100% rH
1. Remove the sensor from the medium.
2. Clean the outside of the sensor carefully with a damp cloth.
3. Allow a temperature compensation time of approx. 20 minutes for the sensor in the
ambient air. Make sure that the sensor is not exposed to any direct ambient effects
(direct sunlight, drafts) during this time.
4. Is the measured value display on the transmitter stable:
Perform the calibration in accordance with the Operating Instructions for the
transmitter. Pay particular attention to the software settings for the stability criteria
for calibration and for the ambient pressure.
5. Where necessary:
Adjust the sensor by accepting the calibration data.
6. Then place the sensor back into the medium.
7. Deactivate the hold status at the transmitter.
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Follow the calibration instructions in the Operating Instructions for the transmitter
used.
7.3.4 Calculation example for the calibration value
As a check, you can calculate the expected calibration value (transmitter display) as shown
in the following example (salinity is 0).
1. Determine the following:
• Ambient temperature for the sensor (air temperature for Air 100% rh or Air variable
calibration types, water temperature for H2O air-saturated calibration type)
• The altitude above sea level
• The current air pressure (= relative air pressure based on sea level) at the time of
calibration. (If indeterminable, use 1013 hPa.)
2. Determine the following:
• The saturation value S acc. to Table 1
• The altitude factor K acc. to Table 2