16 17
• Stir gently and wait a couple of minutes for thermal equilibrium.
Note: The electrode should be submerged approximately 4 cm (1½")
into the solution. The temperature probe should be located as
close as possible to the pH electrode.
• Press °C to display the temperature of the buffer (e.g. 20.0°C).
• Press the pH key to read pH values. Stir
gently and wait for a couple of minutes.
• Adjust the OFFSET trimmer on the front panel until LCD shows the
pH value at the noted temperature (see the pH vs. temperature
chart on page 18).
• Rinse and immerse pH electrode and tem-
perature probe in pH 4.01 or pH 10.01
buffer (2
nd
calibration point); stir gently.
• Wait a couple of minutes and adjust the SLOPE trimmer on the
front panel until the LCD shows the pH value at the noted
temperature.
The pH calibration is now complete.
°C
ºC
pH
HI 7004
OFFSET
pH
SLOPE
pH
PROCEDURE FOR HI 931000
• Turn the meter on.
Note: The "∆" indicator blinks when the reading is not stable.
• Press CAL and the display will flash "7.01 ∆".
• Remove the electrode protective cap, rinse the electrode tip with
some pH 7.01 solution, then immerse the pH electrode and
temperature probe in a pH 7.01 buffer solution.
• Stir gently and wait a couple of min-
utes for thermal equilibrium.
Note: The electrode should be submerged
approximately 4 cm (1½") in the
solution.
• When electrode has stabilized, the "∆" indicator stops flashing.
Press CFM to confirm the first buffer solution.
• To quit the calibration mode and save a one-point (offset)
procedure, press the ON/OFF key. For best accuracy, however, it
is recommended to perform a two-point calibration.
• The LCD will now blink "4.01 ∆".
pH 10.01 can be selected by pressing
the CAL key.
• Rinse the electrode with the second
buffer solution (pH 4.01 or pH 10.01).
• Dip the electrode into the buffer solution, stir gently and wait
until the instability indicator "∆" stops flashing. Press CFM to
confirm the second buffer solution.
The meter is now calibrated and will return to operational mode.
CAL
∆
4 cm
(1½")
∆
CFM
∆
CFM
∆
