6
7
The pH reading is directly affected by temperature. In order for the meter to
measure the pH accurately, temperature must be taken in consideration. If the
sample temperature is quite different from the temperature at which the pH
electrode was kept, allow a few minutes for a perfect thermal equilibrium
between them.
To use the meter's Automatic Temperature Compensation feature, submerge the
temperature probe into the sample as close to the electrode as possible and wait
for a couple of minutes.
If manual temperature compensation (MTC) is desired, the temperature
probe must be disconnected from the instrument
.
The display will show the default temperature of 25°C or the last temperature
set with the "°C" indicator blinking.
The MTC tag and up & down arrows symbols light
up on the LCD to indicate that the meter is in
MTC mode and the arrow keys can be used to
enter the desired temperature value.
Note
: When in MTC the user can press and hold the arrow keys, and the meter
will start incrementing/decrementing the temperature value. The meter
keeps measuring and the display is updated every second.
ORP MEASUREMENTS
To perform ORP measurements, connect an optional ORP electrode (see "Acces-
sories" section) to the meter and turn it ON.
If necessary, enter the "mV" mode by pressing RANGE until the display changes
to mV.
Submerge the ORP electrode tip (4cm/1½") into the sample to be tested and
allow a few minutes for the reading to stabilize.
Measurements within the ±699.9 mV range are displayed with 0.1 mV
resolution, while outside this range the resolution automatically switches to 1
mV.
The ATC (or MTC) tag is turned off because mV readings are not temperature
compensated.
For accurate ORP measurements, the surface of the electrode must be clean and
smooth. Pretreatment solutions are available to condition the electrode and
improve its response time (see “Accessories” section).
INITIAL PREPARATION
The meter is supplied complete with batteries. Remove the back cover, unwrap
the batteries and install them while paying attention to their polarity.
To prepare the instrument for use, connect the pH electrode and the tempera-
ture probe to the BNC and temperature sockets on the top of the instrument.
The temperature probe is used in conjunction with the pH electrode to utilize
the meter's ATC capability, but it can also be used independently to take
temperature measurements. If the probe is disconnected, temperature can also
be set manually with the UP and DOWN arrow keys (see further on for details).
Turn the instrument ON by pressing ON/OFF.
At start-up the display will show all the used segments for a few seconds (or
while the button is held), followed by the percentage indication of the
remaining battery charge, then enters measurement mode.
After measurement switch the meter off, clean the electrode and store it with a
few drops of
HI 70300
storage solution in the protection cap.
The auto-off feature turns the meter off after 20 minutes with no button
pressed. To disable this feature, see “Setup Menu” section on page 9.
pH MEASUREMENTS
To take a pH measurement remove the electrode
protective cap, unscrew the refilling hole cap, and
submerge the tip (at least 4cm/1½") of the
electrode and the temperature probe into the
sample to be tested.
If necessary, press the RANGE key until the display
changes to the pH mode.
Allow for the electrode to adjust and reading to
stabilize (hourglass symbol turns off).
The LCD will show the pH measurement together
with the temperature of the sample.
In order to take more accurate pH measurements, make sure that the
instrument is calibrated (see “Calibration” section for details).
It is recommended that the electrode is always kept wet and rinsed thoroughly
with the sample to be measured before use.
OPERATIONAL GUIDE
