wtw Multi 9420 - Calibration with Comparison Meas. (FDO Comp)

Dissolved oxygen (D.O.) Multi 9420
74 ba75964e04 04/2015
7.3.5 Calibration with Comparison meas. (FDO Comp)
For this calibration procedure, the Comparison meas. setting must be set to on
in the Calibration menu.
Proceed as follows to calibrate the instrument:
2. Place the FDO
®
925 D.O. sensor in the check and storage bea-
ker, FDO
®
Check.
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.
3. Start the calibration with <CAL>.
The last calibration data (relative slope) is displayed.
4. Start the measurement with <ENTER>.
The measured value is checked for stability (stability control).
The [AR] status indicator is displayed. The measured parameter flashes.
5. Wait for the AutoRead measurement to be finished.
The calibration record is displayed and output to the interface.
6. Switch to the measured value display with <ENTER>.
Before calibrating via a comparison measurement, the sensor
should be calibrated in the air calibration vessel.
1. Connect the D.O. sensor to the meter.
2. Immerse the D.O. sensor in the reference solution.
3. Start the calibration with <CAL>.