Hanna Instruments HI 84429 - Manual (Page 35)

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Press LOG to memorize the current reading. A message indicating the free log space will be
displayed for a few seconds.
Up to 50 log samples can be saved into the instrument’s memory. When the free pH log space
is under 12% a message will be permanently shown on the display, indicating the remaining
free log space.
In order to take pH measurements follow the next steps:
• Submerge the tip of the electrode (4 cm/1 1/2’’) and the temperature probe into the sample
to be tested and stir gently. Allow time for the electrode to stabilize. When the reading
becomes stable the (unstable measurement) symbol will disappear.
• If the pH reading is out of range (-2.00 to 16.00 pH) the closest full-scale value (-2.00 pH
or 16.00 pH) will be displayed blinking.
If measurements are taken successively in different samples, it is recommended to rinse the
electrodes thoroughly with deionized water or tap water and then with some of the next sample
to prevent cross-contamination.
The pH reading 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-M 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 at the
temperature of measurements. 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 manually set temperature can now be adjusted with the ARROW keys (from -20.0 to 120.0 °C).