Instruction Manual
PD 300
4.4
Dissolved Oxygen Calibration
Before calibrating your meter, make sure to rinse the probe well with de-ionised water or rinse
solution.
NOTE
Do not let membrane surface of the probe touch any
other surface. The probe guard (the piece with holes
fitted over the end of the probe) protects the membrane;
make sure this is always attached to the probe while it
is in use. See Figure 9.
You can calibrate for dissolved oxygen in either %
saturation or mg/L (ppm).
All new calibrations
automatically override existing DO calibration data.
Figure 9: DO Probe guard
Before Calibration
Before starting calibration, make sure you are in the correct measurement mode. When you
switch on the meter, the meter starts up in the units last used (either pH, mg/L (ppm) or % air
saturation). For example, if you shut off the meter in “mg/L” units, the meter will read “mg/L”
units when you switch the meter on.
NOTE
Most users will calibrate to 100% saturation even when working in mg/L. When calibrating the
meter in mg/L mode, you can make fine adjustments, typically to a mid-range value between
10 and 100%. If you are calibrating to a mid-range value, you need to set the 100% saturation
value first.
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