Hanna Instruments pH 209 - Manual (Page 5)

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