29
28
•
Rinse the electrode and temperature probe
before immersing them into pH 4.01 /
pH 10.01 calibration buffer, stir gently
and wait for thermal equilibrium.
•
The symbol "E5" should disappear and a
temperature compensated buffer value will
flash.
•
Wait until the pH symbol stops flashing.
•
Press CFM to confirm the calibration.
The instrument is now calibrated and will
remain calibrated even when it is turned off.
Note:
the meter will lose the calibration if the battery is removed.
If for some reason the temperature probe is out of order, or a
manual
temperature compensation
is required, follow the procedure below:
•
Make sure the temperature probe is de-
tached.
• Press RANGE to select the temperature
mode.
• Place the pH electrode into the pH 7.01
buffer and shake it briefly. Wait a couple
of minutes for thermal equilibrium.
• Note the temperature of the buffer with a
ChecktempC (or an accurate thermometer),
e.g. 20°C.
•
Use the UP and DOWN arrow keys to adjust the temperature
manually to the above value.
•
Follow the calibration procedure on the previous page.
HI 7004
pH
pH
CFM
RANGE
°C
HI 7007
ºC
PROCEDURE FOR HI 8424
• Switch the meter on after connecting the
pH electrode and the temperature probe.
• Remove the protective cap from the elec-
trode, rinse the tip of the electrode with
some pH 7.01 solution, then immerse the
pH electrode and temperature probe into
a pH 7.01 buffer solution; stir gently and
wait a couple of minutes for thermal equi-
librium.
Note:
the electrode should be submerged
approximately 4 cm (1½") into the
solution. The temperature probe should
be close to the pH electrode.
•
Press RANGE to display pH measurement.
• Press CAL. A temperature compensated buffer value together with
the pH symbol will be displayed, e.g. if the temperature is 25°C,
the display will show "pH 7.01". If the buffer temperature is
20°C, the display will show "pH 7.03" (see page 35).
If "E4" appears, the calibration solution is
wrong or is out of specifications and needs
to be replaced.
• Wait until the "pH" symbol stops flashing
which means that the reading is stable.
•
Press CFM. The symbol "E5" will appear to indicate that offset
calibration is complete but the electrode is still in pH 7.01 buffer,
and the meter expects a pH 4.01 or 10.01 buffer.
ON
OFF
HI 7007
4 cm
(1
½
")
RANGE
CAL
pH
pH
CFM
