Hanna Instruments HI 84502 - Manual (Page 34)

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In order to take pH measurements, follow the next steps:
• Submerge the pH electrode 2 cm (0.8’’) and the temperature probe into the sample to be
tested and stir gently. Make sure the PTFE junction is completely submersed. Allow time for
the electrode to stabilize. When the reading becomes stable the
(unstable measurement)
symbol will disappear.
• If the pH reading is less than -2.00 pH or greater than 16.00 pH, the closest full-scale value
will be displayed blinking.
During pH measurements with stirrer on, the stirrer icon will be displayed. In case of a stirrer
malfunction, the stirrer will stop and the stirrer icon will start blinking.
If measurements are taken successively in different samples, it is recommended to rinse the
electrodes thoroughly with deionized or distilled water and then with some of the next sample
to prevent cross-contamination.
The pH measurement is affected by temperature. In order to have accurate pH measurements,
the temperature effect must be compensated for. To use the Automatic Temperature Compensation
(
ATC) feature, connect and submerge the HI 7662-T temperature probe into the sample as close
as possible to the electrode and wait for a few seconds. The “ATC” message will be shown on
the display. Automatic Temperature Compensation will provide pH corrected values for the
measured temperature. If Manual Temperature Compensation (
MTC) is desired, the temperature
probe must be disconnected from the instrument.
The default temperature of 25 °C (77 °F) or the last temperature reading will be displayed,
preceded by the symbol and the
“MTC” message.
The temperature can be adjusted with the ARROW keys (from -20.0 to 120.0 °C).