Hanna Instruments HI 98280 - Manual (Page 34)

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4.3 DISSOLVED OXYGEN CALIBRATION
If the DO % saturation range is calibrated, the DO concentration range will also
be calibrated, and vice versa.
The DO % saturation value is referred to the DO concentration in air (100%).
For this reason it is recommended to calibrate the probe near the area where the
measurements will be taken.
Also note that the DO concentration values are based on DO % saturation,
temperature, salinity and atmospheric pressure. It is recommended to use a stan-
dard solution or a reference DO meter to compare readings during calibration.
The calibration of the DO % saturation range can be performed at 1 or 2 stan-
dard points (0% and 100%), or at a single custom point (50 to 500%).
The calibration of the DO concentration range can be performed at a single
custom point (4 to 50 mg/L).
Choose the “DO calibration” from the “Calibra-
tion” menu, select the DO calibration type using
the arrow keys and press <OK> to confirm.
DO % saturation
The default first calibration point is 100 %.
• Fill the calibration beaker with approximately 4 mm (5/32”) of distilled water
and screw it onto the probe.
• The message “Not ready...” is displayed until a
stable reading is reached.
• To change the calibration value, press the <Cal.
point> softkey and select the desired point.
• To insert a different calibration value, press
<Cal. point> and then <Custom>. Insert the
desired value using the keyboard.
• When the reading is stable, the “Ready” mes-
sage is displayed. Press <Confirm> to store
the calibration point.
• After the first calibration point is confirmed, put the probe in a zero oxygen
standard solution and wait for stable reading.
• Press <Confirm> to store the calibration point.