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5.5.1 According to the pH isothermal measurement principle, the closer the test sample’s temperature is to
the calibration solution’s, the higher the accuracy of the measurement. This principle is recommended to
follow when conducting tests for the best result. Example: If users were to test samples at 150˚F, we
recommend warming up the calibration solutions to the same temperature before performing calibrations in
order to get the most accurate readings.
5.5.2 The instrument has a function to return to factory default setting, which can be set up in P5 (refer to
section 5.6). Returning to factory default setting is to restore the meter to theoretical value (zero potential pH
is 7.00, slope is 100%), and set all the parameters to default settings. When the meter’s calibration or
measurement is performing abnormally, users can use this function to let the meter return to factory default
mode, and then conduct calibration and test again. Please note that this function is irreversible once used.
5.5.3 Self-Diagnosis
In the process of calibration and measurement, the meter has a self-diagnosis function. Please see table 5.
Table – 5 Self-diagnosis Information
Display
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Contents
How to fix
Wrong pH buffer solution or the buffer
solution is out of range.
1.
Check whether pH buffer solution is correct.
2.
Check whether the meter connects the
electrode properly.
3.
Check whether the electrode is damaged.
4.
Make sure there is no bubble in the
electrode’s bulb.
pH electrode zero electric potential
out of range (<-60mV or >60mV)
1.
Make sure there is no bubble in the
electrode’s bulb.
2.
Check whether the electrode is damaged.
3.
Check if pH buffer solutions are correct.
4.
The pH Electrode is aged. Replace a new
one.
pH electrode slope is out of range
(<85% or >110%)
Press key when reading is not
stable during calibration.
Press key
when icon appears and stays
on the screen.
During calibration, the measuring value
is not stable for ≥3min.
1.
Make sure there is no bubble in the
electrode’s bulb.
2.
Check whether the electrode is damaged.
3.
The pH Electrode is aged. Replace a new
one.
* If you find any air bubble in the glass bulb of the pH sensor, simply shake the probe for a few times
to remove it. The existence of an air bubble in the glass bulb will significantly decrease the stableness
of measurement.