Xylem MultiLab 4010-2 - Manual (Page 48)

Dissolved oxygen (D.O.) MultiLab 4010-2
48 ba76142e01 05/2013
Criteria for a stable
measured value
The Stability control function checks whether the measured values are stable
within the monitored time interval.
The minimum duration until a measured value is assessed as stable is the mon-
itored time interval. The actual duration is mostly longer.
7.1.2 Measuring the temperature
For reproducible D.O. measurements, it is essential to measure the tempera-
ture of the test sample.
IDS D.O. sensors measure the temperature with a temperature sensor inte-
grated in the IDS sensor.
7.2 Calibration
7.2.1 Why calibrate?
D.O. sensors age. This changes the zero point (asymmetry) and slope of the
D.O. sensor. As a result, an inexact measured value is displayed. Calibration
determines and stores the current values of the zero point and slope.
7.2.2 When to calibrate?
 When the calibration interval has expired
 When your accuracy requirements are especially high
 Routinely within the framework of the company quality assurance
7.2.3 Calibration procedures
The MultiLab 4010-2 provides 2 calibration procedures:
3. Using <ENTER>, start a further measurement with stability control.
or
Release the frozen measured value again with <AR> or <M>.
The [AR] status display disappears. The display switches back to the
previous indication.
Measured parameter Time interval Stability in the time
interval
D.O. concentration 20 seconds Δ : better than 0.03 mg/l
D.O. saturation 20 seconds Δ : better than 0.4 %
D.O. partial pressure 20 seconds Δ : Better than 0.8 mbar
Temperature 15 seconds Δ : Better than 0.5 °C