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Preparation
Accessories lists Hanna Instruments solutions used for ORP calibrations. The calibration should be
conducted at temperatures between 20‑26 °C. The sensor should be clean and oil free.
Procedure
• From the “Calibration” menu select “Single param. calibration” and then “ORP” calibration. The
display shows two options: “Custom ORP” and “Restore
factory calib.”.
• For a user calibration select “Custom ORP”.
• Fill a beaker with an ORP test solution (see Accessories).
• Using the keypad, insert the numerical ORP value and then
press <Accept> to confirm.
• The stability counter will count down and the message
“Ready” and <Confirm> will be displayed.
• Press <Confirm> to accept the calibration point.
• After confirmation, the following messages are displayed:
“Storing” and “Calibration completed”.
• Press OK to return to the Calibration menu.
• Press <Measure> to return to the measurement screen.
• To restore the factory calibration data, select the corresponding option in the “ORP calibration”
menu and then press <Select>.
The accuracy of dissolved oxygen measurements is directly related to membrane cleanliness and
calibration technique. Oily coating and biological contaminants are the primary cause of calibration drift
in dissolved oxygen sensors. Unfortunately, brushes or other cleaning objects may damage the membrane.
Replacing the membrane cap and electrolyte is the best way to perform periodic maintenance.
Although it may be easier to calibrate the D.O. sensor prior to deployment, it is advised to calibrate
at the site of deployment. Errors in measurement may result if altitude and barometric pressure differ
between the calibration and measurement site. This is very important for autonomously logging probes.
Note: Perform either the % D.O. Saturation or D.O. Concentration calibration.
ORP CALIBRATION
D.O. CALIBRATION
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