TriOxmatic
®
690
Measuring / Operation
9
ba25314e05
09/2020
4
Measuring / Operation
4.1
Measuring
WARNING
Contact with the sample can lead to danger to the user!
Depending on the type of sample, suitable protective measures
must be taken (protective clothing, protective goggles, etc.).
For measuring submerse the operable sensor in the test sample. The
measured value is available immediately on submersing.
Minimum approach flow
The minimum required approach flow at the sensor must be present
during measurement (see chapter 7 T
approach flow can, e.g. be present due to:
natural movement of the water (flow rate, sea disturbance)
turbulences in the activated sludge basin.
4.2
Calibration
4.2.1
General information on calibration
Why calibrate?
During the operation of a D.O. sensor, the slope of the D.O. sensor
changes with time. The calibration procedure determines the current
slope of the sensor.
When to calibrate?
Calibrate before measuring and at regular intervals (depending on the
application).
Calibration procedure,
Ideally, calibration takes place in water vapor-saturated air. To do so,
position the sensor approx. 2 cm above a water surface, for example in
a narrow bucket or similar container with water.
In the case of air temperatures under 5 °C we recommend to calibrate
not in air but in air-saturated water that has a higher temperature. You
obtain air-saturated water by pouring water several times in and out of
two vessels so that it sparkles.
Do not suspend the sensor on the sensor connection cable.
Use a sensor holder or armature. Information on this and
other TriOxmatic
®
690 accessories is given in the WTW
catalog and on the Internet.
