9
8
HI 7004
HI 7007
HI 7004
IMPORTANT
The instrument's pH range should be re-calibrated:
• When the meter is new.
• Whenever the pH electrode is replaced.
• At least once a month.
• After use in aggressive chemicals.
• After cleaning procedure and changing the reference electrolyte.
• For greatest accuracy.
INITIAL PREPARATION
Pour small quantities (up to 4cm / 1½" level)
of pH 7.01 (
HI 7007
) and pH4.01 (
HI 7004
)
or pH 10.01 (
HI 7010
) solution into clean
beakers. If possible use plastic beakers to
minimize any EMC interferences.
If you are measuring in the acid range, use pH 4.01 as second
buffer; if you are measuring in the alkaline range, use pH 10.01 as
second buffer.
For accurate calibration, use two bea-
kers for each buffer solution; the first
for rinsing the electrode, the second
for calibration. In this way, contami-
nation of the buffer is minimized.
Note:
The electrode should be submerged approximately 4 cm (1½")
into the solution.
Note:
If you need to calibrate to NBS standards, use pH 6.86 (
HI
7006
) and pH 9.18 (
HI 7009
) instead of pH 7.01 and 10.01
respectively.
Use a
ChecktempC
or a glass thermometer as reference.
PROCEDURE
• Switch the instrument on by pressing the
ON/OFF button.
• Rinse and immerse the pH electrode into
pH 7.01 buffer and shake briefly. Wait for
the reading to stabilize.
pH CALIBRATION
• Note the temperature of the buffer solution using
a
ChecktempC
or a glass thermometer
(e.g.20°C).
• Press the °C key to select temperature setting.
• Adjust the Temperature knob until the LCD shows the noted
temperature.
• Press the pH key to select pH measurement.
• Wait a couple of minutes and adjust the OFFSET knob until
display shows the pH value at the noted temperature (see the pH
versus temperature chart).
• Rinse and immerse the pH electrode in pH 4.01/pH 10.01 buffer
and shake briefly.
• Wait a couple of minutes and adjust the SLOPE knob until
display shows the pH value at the noted temperature (see the pH
versus temperature chart).
• The pH calibration is now complete.
4 cm
(1½")
HI 7007
RINSE
HI 7007
CALIBRATION