9
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.
e) When the calibration time-out is expired (if feature is enabled).
PROCEDURE
The meter offers a choice of 7 memorized buffers (1.68, 4.01, 6.86,
7.01, 9.18, 10.01 and 12.45 pH) and also allows the user to enter
two more pH values for calibration, C1 and C2 (see Custom Buffer
Selection section on page 12 for details).
Pour small quantities of selected buffer solutions into clean beakers.
For accurate calibration use two beakers for each buffer solution, the
first one for rinsing the electrode and the second one for calibration.
Remove the protective cap and rinse the electrode with some of
the buffer solution to be used for the first calibration point.
TWO-POINT CALIBRATION
Press the CAL key. The "CAL" and " " indicators will be
displayed. The secondary LCD will display buffer "7.01". If a
different calibration buffer is desired (e.g. 6.86), use the UP
and DOWN arrow keys to change the displayed value.
Submerge the electrode approximately 4 cm (1½") into the
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
" and "WRONG "
will blink alternatively;
if it is close to the selected buffer the
meter will advise the user with an
acoustic signal (if enabled) when the
reading becomes stable and the display
will change to "READY" and blinking "CFM".
or
20
TROUBLESHOOTING GUIDE
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