Hanna Instruments HI 2221 - Manual (Page 8)

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probe approximately 3 cm (1¼”) into the sample to be tested and stir
gently. Allow time for the electrode to stabilize.
• The pH is displayed on the primary LCD and the temperature on the
secondary LCD.
• The pH reading is out of range, the closest full-scale value will be
displayed blinking on the primary LCD.
• It is also possible to view the mV reading by pressing the RANGE key.
If measurements are taken successively in different samples, it is
recommended to rinse the electrode 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 measure the pH
accurately, this temperature effect must be compensated for. To use the
Automatic Temperature Compensation feature, connect and submerse
the HI 7662 temperature probe into the sample as close to the electrode
as possible and wait for a few minutes.
If the temperature of the sample is known, manual
compensation can be performed by disconnecting the
temperature probe.
The display will show the last recorded temperature
reading with the “°C” symbol blinking.
The temperature can now be adjusted with the ARROW keys (from
-20.0 ºC to 120.0 ºC).
ORP MEASUREMENTS ORP MEASUREMENTS ORP MEASUREMENTS ORP MEASUREMENTS ORP MEASUREMENTS
An optional ORP electrode must be used to perform ORP measurements
(see Accessories).
Oxidation-Reduction Potential (REDOX) measurements provide the
quantification of the oxidizing or reducing power of the tested sample.
The surface of the ORP electrode must be clean and smooth in order to
obtain an accurate measurement.
C
MTC
C
SLOW FAST POOR GOOD
mV
C
ATC