horiba LAQUAact-PD110, Instruction Manual, Page: 63 / 117

Dissolved oxygen measurement
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Performing measurement
You can perform measurement in the measurement mode by immersing the DO
electrode in the sample. Also, you can use the automatic hold function to judge the
stability of the measured value. The automatic hold function has two modes, the auto
stability mode and the auto hold mode. For the instruction to set the mode, refer to
"Setting the auto stability and auto hold function" (page 64).
1. Press the key to change the parameter to
measure.
2. Clean the membrane at the tip of the DO
electrode with pure water (or deionized water)
and wipe it with a soft cloth at least 10
minutes before calibration.
Be careful not to break the membrane at the tip
of the electrode.
3. Immerse at least 6 cm from the tip of the DO
electrode in the sample solution.
In order to immerse the temperature sensor in
the standard solution, make sure to immerse the
electrode surely.
During measurement, use a stirrer to stir the
sample solution at 1000 rpm to 1500 rpm.
Note
When using an electrode "9551-20D" or "9551-100D", immerse at least 9 cm from the tip.
4. Immerse the DO electrode in the sample solution.
Stability judgment starts and the DO icon blinks. When the value is stabilized, the DO
icon changes from the blinking state to the lit state and the display is fixed to the
measured value at the stable time.
For the auto stability mode, if the measurement DO value does not meet stability
condition, the fixed value is released. When the measured value meet stability
condition again, the measured value is fixed. For the auto hold mode, press the
key to release fixed the measurement value. When the measured value meet stability
condition again, the measured value is fixed.
Stabilized