Hanna Instruments HI 902 Color, Quick Start Manual

Page: 9 / 248

9
QUICK START GUIDE
HOW TO CALIBRATE A pH ELECTRODE
To enter pH calibration mode, press then to enter pH mode. Once in pH
mode, press to enter pH calibration mode.
PREPARATION
Pour small quantities pH 4.01, pH 7.01 and pH 10.01 buffer solutions into clean beakers. If
possible, use plastic beakers to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use two beakers for each
buffer solution: one for rinsing the electrode and one for calibration.
CALIBRATION PROCEDURE
Three buffer entry types are available: Automatic, Semi-automatic and Manual Selection.
The default option is Manual Selection.
• If the instrument has been previously calibrated and calibration was not cleared, the old
calibration can be cleared by pressing
.
Note: It is very important to clear calibration history when a new electrode is used
because most errors and warning messages that appear during calibration depend
on calibration history.
• Use the or to select pH 4.01 buffer solution.
• Use the second beaker of pH 4.01 buffer solution to rinse the pH electrode, temperature
probe and propeller stirrer.
• Immerse the pH electrode, temperature probe and propeller stirrer in the pH 4.01 buffer
solution. The pH electrode’s bulb must be completely immersed in the buffer solution and
the reference junction needs to be 5-6 mm below the surface. Add additional buffer if
necessary.
• Press to turn on the propeller stirrer.
• Once the reading has stabilized, press to update the calibration.
• Repeat this procedure for pH 7.01 and 10.01 buffer solutions.
• Press to accept and exit pH calibration mode.
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