7.3.1.1 Calibrating the pH sensor
To ensure a high level of measuring accuracy, adjust the pH
sensor at set time intervals. This calibration interval seriously
depends on the application of the pH sensor and on the required
measurement accuracy and reproducibility. The calibration interval
can vary between daily and every few months.
Tab. 3: Valid calibration values
Assessment
Zero point
Slope
Very good
-30 mV … +30 mV
56 mV/pH … 60 mV/pH
Good
-45 mV … +45 mV
56 mV/pH … 61 mV/pH
Acceptable
-60 mV … +60 mV
55 mV/pH … 62 mV/pH
If you measure the pH with potential equalisation,
set this [Potential equalisation] procedure as a
parameter when selecting the measured variable
as a parameter.
Calibrate the pH-sensor for the function: pH com‐
pensation for chlorine measurement
It is mandatory that the pH measurement is always
calibrated first, followed by the chlorine measure‐
ment. Calibration of the chlorine measurement
should always follow every further calibration of the
pH measurement, otherwise the chlorine measure‐
ment will be inaccurate.
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