32
To set the Alarm Limits:
• Press
while in
pH Measure
mode.
• Press
.
• Use
or
to select the Alarm option.
• Press
and use
or
to highlight the
Alarm Limits option.
• Press
and use
/
to select next/
previous entry to be edited.
• Press
and use
or
to set the desired
value, then press
to save the modified value.
• Press
to return to the Alarm options. The modified option is saved automatically.
Isopotential Point
This option allows the user to edit the isopotential point of the electrode used for pH measurements. The
isopotential point is the mV reading for an electrode at which temperature has no effect on the measurement. The
ideal electrode has an isopotential point of 0.0 mV and 7.00 pH, while an actual electrode typically deviates
slightly from the ideal values.
If the actual isopotential pH for an electrode is known, it can be set by accessing this option.
Note
: If the isopotential point has been modified, recalibration must be performed.
To set the Isopotential Point:
• Press
while in
pH Measure
mode.
• Press
.
• Use
or
to select the Isopotential Point option.
• Press
and set the desired isopotential pH value using
or
.
• Press
to save the current value or press
to
cancel operation.
49
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 channel first for -
HI 5222
only).
• Select the Direct reading mode (see mV Setup for details).
• Place the tip of the ORP electrode 4 cm (1.5”) 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, “
----
” will 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 channel first for -
HI 5222
only).
• Select the Direct/AutoHold reading mode (see mV Setup for
details).
• Place the tip of the ORP electrode approximately 4 cm (1.5”)
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, “
----
” will be displayed on the LCD.
