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mV & Relative mV MEASUREMENTS
mV/ORP MEASUREMENTS
Oxidation-reduction potential (ORP) 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.
DIRECT MEASUREMENT
To measure the mV of a sample using the Direct reading mode:
• Press
and then
to enter
mV Measure
mode.
• Select the Direct reading mode (see mV Setup for details).
• Place the tip of the ORP electrode 4 cm (1
1
/
2
”) into the
sample to be tested and allow a few seconds for the reading
to stabilize.
• The instrument will display the measured mV value on the
LCD.
Note
: If the reading is out of range, “
----
” may be displayed
on the LCD.
DIRECT/AUTOHOLD MEASUREMENT
To measure mV of a sample using the Direct/AutoHold reading
mode:
• Press
and then
to select
mV Measure
mode.
• Select the Direct/AutoHold reading mode (see mV Setup for
details).
• Place the tip of the ORP electrode approximately 4 cm (1
1
/
2
”)
into the sample to be tested.
• The measured mV value will be displayed on the LCD. Press
and the “
AutoHold
” indicator will start blinking on
the LCD until the stability criterion is reached. The mV value
will be frozen on the LCD, along with “
AutoHold
” indicator.
• To return to normal
Measure
mode press
.
Note
: If the reading is out of range, “
----
” may be displayed
on the LCD.
• To return to normal
Measure
mode press
.
Note
: If the reading is out of range, “
----
” will be displayed on the LCD.
Outside Cal Range
warns the user if the current reading is out
of the calibrated area. The calibrated area is that part of the pH
range in which the calibration point assures an accurate reading.
If the reading is taken out of the calibration area, the “
Outside
Cal Range
” message will start blinking on the LCD. The
calibrated area is calculated in accordance with the pH resolution
used during the measurement. To avoid triggering this message,
the buffer values have to be well distributed in the desired
measurement range.
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 before
immersing it into the next sample solution.
The pH reading is affected by temperature. In order to measure the pH accurately, the temperature effect
must be compensated. To use the
Automatic Temperature Compensation (ATC)
feature, connect and
place the
HI 7662-T
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,
Manual Temperature Compensation (MTC)
can be used by
disconnecting the temperature probe.
Notes
: • For mV/Rel mV measurements “
NoProbe1
”/“
NoProbe2
” or “
TEMP1
”/”
TEMP2
” will be displayed.
• For the other measurements “
MTC1
”/“
MTC2
” or “
ATC1
”/“
ATC2
” indicators will be displayed.
• When in MTC mode, the temperature can be modified by pressing
for
mV
/
Rel mV Measure
mode and
for
other Measure
mode, if the Reading Mode option is Direct.
• The temperature value can be adjusted with
or
from -20.0 °C to 120.0 °C. Press
to save the new temperature value or press
to return to
Measure
mode without
changing the MTC value.
• When in ATC mode “
----
” will be displayed on the LCD if the ATC signal is under or over the
temperature range (-20.0 °C to 120.0 °C).
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