17
pH CALIBRATION
It is recommended to calibrate the instrument frequently,
especially if high accuracy is required.
The pH range should be recalibrated:
a) Whenever the pH electrode is replaced
b) At least once a week
c) After testing aggressive chemicals
d) When extreme accuracy is required
PREPARATION
The user can choose among 7 memorized buffers (pH
1.68, 4.01, 6.86, 7.01, 9.18, 10.01 and 12.45).
•
Pour small quantities of selected buffer solutions into
clean beakers. For accurate calibration use two bea-
kers for each buffer solution, the first one for rinsing
the electrode and the second one for calibration.
•
Remove the tip protection bottle and rinse the elec-
trode with some of the buffer solution to be used for
the first calibration point.
20
•
Press CFM to confirm the calibration
and the meter will store the first cali-
bration point. The primary LCD will
show the calibrated reading, while the
secondary LCD will show the second
expected buffer (pH 4.01).
•
If a different calibration buffer is desired, select the
appropriate value with the arrow keys.
•
After the first calibration point is confirmed, submerge
the electrode tip approximately 4 cm into the second
buffer solution, place the temperature probe as close
as possible to the electrode and stir gently.
•
The LCD will flash NOT READY for 12 seconds.
Then, if the reading is not close to the selected buffer,
WRONG BUFFER and WRONG ELECTRODE
will blink alternatively; if it is close to the selected
buffer, the calibration is performed and the display
will show READY and blinking CFM.
