Note: Automatic temperature compensation during calibration
i
Both the signal of the pH electrode and the pH value of the calibration solutions
depend on the temperature. If a temperature sensor is connected, the tempe-
rature influence of the electrode is automatically compensated both during measurement
and during calibration. Otherwise, the actual temperature of the buffer in question should
be entered as accurately as possible. If standard or DIN buffers are used, the temperature
influences of the buffers are also compensated. With manual buffer selection, the pH
values of the buffers should be entered at the associated temperature in order to achieve
as accurate a calibration process as possible
5.3 Calibration reminder
Set a reminder to regularly check the calibration data: (<SEt PArA>: C.int). The time interval
chosen depends on the use and stability of the electrode. As soon as the interval expires,
>CAL< flashes in the display as a reminder.
5.4 Calibration data memory
The last 16 calibrations (with information on the measurement result and date) are
stored in the instrument. Stored calibration data can be read both with the PC software
GSOFT3050 or in the <rEAd CAL> menu (see Chapter 4.3).
5.5 pH measurement
pH measurement is a very precise but also sensitive measurement. The signals measured
are very weak (high Ohm), especially if measurements are carried out in low-ion media.
Care should therefore be taken to ensure that
• Errors, such as those caused by electrostatic charge, are avoided
• Plug contacts are kept clean and dry
• Electrodes are not immersed beyond the length of the shaft
• The electrode is calibrated sufficiently often – the frequency of calibration depends on
the electrode and its use, and can vary from every hour to several weeks
• A suitable electrode is used
a)
b)
SD_305_pH/ORP_1 04/2021
Rinse the electrode with distilled or deionised water
and dab the electrode carefully with a paper towel.
Immerse the pH electrode (temperature probe incl.) in the
sample solution. Ensure sufficient flow, e.g. by
a) using a magnetic stirrer with agitator (recommended)
or
b) swirl the pH electrode in the solution.
The pH value can be read off in operating mode.
Stop stirring while doing this. A stable measurement
value is indicated by the indicator arrow over "ok".
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