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7.2.2 Procedure
The measured pH value is displayed, along with the temperature and the buffer
value on the second level.
If necessary, press the
Cal point
softkey and use the arrow keys to select the
correct buffer.
• Immerse the sensors in the first buffer rinse
solution and stir gently.
• Immerse the pH sensor and temperature
probe into the selected buffer and stir gently.
The temperature, pH buffer value and the “Not
ready” message are displayed.
• Once the reading has stabilized the countdown
timer will count down until the display shows the
“Ready” message.
• Press
Confirm
to accept the calibration point.
• After the calibration point is confirmed, to avoid
cross-contamination immerse the sensors in the next calibration buffer rinse
solution and stir gently.
• Press
Cal Point to
select the next buffer (if necessary), and repeat the calibration
procedure outlined above with the second and third buffers.
Note
The calibration procedure can be terminated after a single or 2 point
calibration by pressing
ESC
. The message “Storing” followed by “Calibration
completed” will be displayed.
• Press
OK
to return to the Calibration menu.
• Press
Measure
to return to the measurement screen.
Custom buffer calibration
• The
HI 9819X
permits a single custom buffer to
be used for pH calibration. This can be used
along with standard buffers as part of a 2 or 3
point calibration or as a single point.
• To select this option first press
Cal. point
and
then
Custom
while the meter is waiting for stable
reading.
• A text box window will appear. Use the keypad to enter the value of the buffer at
the current temperature. The valid range for custom a buffer is from 0.00 to
14.00 pH.
• Unscrew the calibration beaker and empty the solution.
• Shake any remaining liquid off the probe and beaker. No droplets should remain
on the D.O. sensor membrane.
Note
Do not attempt to dry wipe the D.O. sensor as damage to the membrane
may occur.
• Screw the empty calibration beaker on the probe body. The beaker should not
be dry.
• Press
Accept
to close the displayed message.
• When the measurement is stable, “Ready”
appears. Press
Confirm
to store the calibration
data and the “Storing” message will appear.
• Press
OK
to return to “Calibration” menu.
Note
To quit the quick calibration procedure,
press
ESC
at any time.
After every calibration the quick calibration window will show a check mark in
the box next to the calibrated parameter.
7.2 pH CALIBRATION
To optimize the pH measurement follow the general guidelines mentioned in the
Chapter 7 introduction.
From the “Calibration” menu select “Single param.
calibration” and then “pH calibration”. The display
shows two options: “Calibrate pH” and “Restore
factory calib.”.
If a new pH sensor has been installed use “Restore
factory calib.” before performing a user calibration
as some warning messages are based on changes from previous calibrations.
If “Restore Factory Calib” is selected, all user calibration data will be deleted and
the default calibration is restored. A user calibration should follow immediately.
If “Calibrate pH” is selected, the user can perform a new calibration using up to
3 buffers (pH 4.01, 6.86, 7.01, 9.18, 10.01 or one custom buffer).
When a 3-point calibration is performed, all old data are overwritten, while with
a single or 2-point calibration the meter will also use information from the previous
calibration, if exists.
7.2.1 Preparation
Pour small quantities of the selected buffer solutions into clean beakers. To
minimize cross contamination, use two beakers for each buffer solution: the first
one for rinsing the sensor and the second one for calibration.
