Hanna Instruments HI 110 - Manual (Page 9)

9
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, the temperature effect must be compensated for. To use the
Automatic Temperature Compensation feature, connect and submerge the
HI 7669/2W temperature probe into the sample as close as possible to the
electrode and wait for a few seconds.
If the temperature of the sample is known, simple manual compensation can
be performed by disconnecting the temperature probe.
The display will then show the default temperature of 25 ºC or
the last temperature reading with the “ºC” tag blinking.
The temperature can now be adjusted with the ARROW keys
(from –9.9 ºC to 120.0 ºC).
mV/ORP MEASUREMENTS (HI 111 and HI 113)
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.
To correctly perform a REDOX measurement, the surface of
the ORP electrode must be clean and smooth.
• Press RANGE to enter mV range.
• Submerge the tip of the ORP electrode 4 cm (1½”) into
the sample to be tested and allow a few seconds for the
reading to stabilize.
• The instrument displays the mV reading on the primary LCD and the
temperature on the secondary LCD.
• If the reading is out of range, the closest full-scale value will be displayed
blinking on the primary LCD.
C C
mV
mV