Hanna Instruments HI 98186 - Manual (Page 29)

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The hourglass icon will be shown on the display until the reading becomes
stable.
When the reading is stable and close to the selected buffer, the CFM
functional key is displayed.
Press CFM to confirm the calibration point.
The instrument will return to the main screen and will memorize the slope
calibration data.
Two points automatic calibration
Submerge the probe into HI 7040 zero oxygen solution and stir gently for
2-3 minutes.
Press CAL. The calibration menu will be displayed.
Press DO to select the DO calibration. The DO calibration screen will be
displayed and the standard 0% saturation (0 mg/L) will be automatically
selected.
The hourglass icon will be shown on the display until the reading becomes
stable.
When the reading is stable and close to the selected standard, the CFM
functional key is displayed.
Press CFM to confirm the calibration point.
The meter will automatically select the 100% saturation (8.26 mg/L) stan-
dard.
Leave the probe in air.
The hourglass icon will be shown on the display until the reading becomes
stable.
When the reading is stable and close to the selected standard, the CFM
functional key is displayed.
Press CFM to confirm the calibration point. The instrument will return to the
main screen and will memorize the calibration data.
One point manual calibration
First determine the dissolved oxygen value of the sample (use a Winkler
titration). Place the probe in the sample and provide adequate stirring.
Access the DO calibration screen as described in the previous DO calibration
procedures.