Stratos Multi E401N
122
6.6.1 Calibration/Adjustment Methods
• In air/water: Automatic calibration in water/air
• Data entry: Data entry of premeasured sensors
• Product: Product calibration by entering saturation %air, concentration, or partial pressure
• Zero point: Zero correction
• Temperature: Temperature probe adjustment
6.6.2 Calibration Mode: In Air
Automatic Calibration in Air
The slope is corrected using the saturation value (100 % Air), similar to the air saturation of water.
Since this analogy only applies to water-vapor saturated air (100 % relative humidity) and often the
calibration air is less humid, the relative humidity of the calibration air must also be specified. If you do
not know the exact value of the relative humidity of the calibration air, you can take the following
reference values for a sufficiently precise calibration:
• Ambient air: 50 % rel. humidity (average)
• Bottled gas (synthetic air): 0 % rel. humidity
Calibration Procedure
Note:
The sensor membrane must be dry. Be sure to keep temperature and pressure constant during
calibration. If there is a temperature difference between calibration and measured media, the sensor
requires some equalization time before and after calibration.
Calibration
[I] [II] … Oxy
When you access calibration, the calibration values selected in the calibration presettings are used.
These settings can still be changed in the Calibration menu. If you do not want to perform calibration,
use the left
softkey
to go back one level and abort the calibration.
01.
Select “In Air” calibration mode.
02.
Take the sensor out of the medium and clean it.
03.
Carefully dab the membrane dry with a paper tissue.
04.
Expose the sensor to air with a known water vapor saturation and press
enter
to confirm.
✓
Display of selected calibration medium (air)
05.
Enter relative humidity, e.g.: Ambient air: 50 %, Bottled gas: 0 %
06.
Enter Cal Pressure:
Enter the calibration pressure if “Manual” was configured.
07.
Start with the
right softkey: Next
✓
Drift check is carried out.
The following parameters are displayed: Sensor current, calibration pressure and response time.
The time for the measuring voltage to stabilize can be shortened with the
left softkey: Exit
(without
drift check: reduced accuracy of calibration values). The response time indicates how long the sensor
needs until the measuring voltage is stable. If the sensor voltage or the measured temperature
fluctuate considerably or the sensor is inadequately polarized, the calibration procedure is aborted
after around 2 minutes. In this case, calibration needs to be restarted. Return the sensor to the process
once this has been successfully completed. Make sure that the temperature of the sensor and the
temperature of the buffer solution are not too far apart. The ideal temperature is 25 °C/77 °F.
08.
Exit calibration with the
right softkey: Next
.
Result
✔
By pressing the
right softkey: Adjust
, the calibration values obtained during calibration for
calculation of the process variables are applied to the device. When using a Memosens sensors,
the calibration values are saved in the sensor.
