Dissolved oxygen
Multi 3620 IDS
52
ba77169d06
10/2021
Example:
– Required accuracy: ± 2 %.
– In water vapor-saturated air or air-saturated water, the nominal
value for the relative D.O. saturation (abbreviated: saturation) is
100 %.
– Therefore, the validity scope is 98 ... 102 %
– The check resulted in a measured value of 99.3 %
The measurement error is within the specified validity scope.
No cleaning or user calibration is required.
7.3
Calibration
7.3.1 Why calibrate?
D.O. sensors age. This changes the slope of the D.O. sensor. Calibration deter-
mines the current slope of the sensor and stores this value in the instrument.
7.3.2 When to calibrate?
If your evaluation of the FDO
®
Check procedure suggests a calibration
When the calibration interval has expired
When your accuracy requirements are especially high
Routinely within the framework of the company quality assurance
7.3.3 Calibration procedure
Calibration in water vapor-saturated air.
To calibrate the
FDO
®
925 use the calibration and storage beaker.
7.3.4 Calibration in water vapor-saturated air
Proceed as follows to calibrate the D.O. sensor:
The
FDO
®
925 D.O. sensor ages so little it does not have to be
regularly calibrated.
To detect changes of the sensor as early as possible, the FDO
®
Check procedure can be useful (see section 7.2).
1.
Connect the D.O. sensor to the meter.
2.
Place the
FDO
®
925 oxygen sensor in the check and storage beaker.
The sponge in the check and storage beaker must be moist (not
wet). Leave the sensor in the check and storage beaker long
enough so it can adapt to the ambient temperature.
