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15.1.1
Calibrating the pH Sensor
Tab. 7: Valid calibration values
Evaluation
Good
Acceptable
CAL Cl
Last calibration 31.03. 2013 13:11:11
Slope
Zero point
Slope calibration
Calibration of zero point
Fig. 32: [Calibration] display with the example of [Chlorine].
Calibration of the measuring channels
The calibration processes are identical for all
measuring channels. However, it is necessary to
calibrate each measuring channel separately.
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.
Zero point
-30 mV ... +30 mV
-60 mV ... -30 mV
+30 mV ... +60 mV
If you measure the pH with potential equalisation,
set the [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 and then the chlorine measurement.
All other calibration of the pH measurement must
always be followed by calibration of the chlorine
measurement. Otherwise the chlorine measure‐
ment will be inaccurate.
Calibrating the controller diaLog DACb
100 %
4.00 mA
Slope
-55 mV/pH ... -62 mV/pH
- 40 mV/pH ... -55 mV/pH
-62 mV/pH ... - 65 mV/pH
A1039
71
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