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15.1.1.4 Calibration of the pH Sensor (CAL) by
[Data Input]
Data input
With the [Data input] calibration method, the known
data of the sensor is entered in the controller. Cali‐
bration by data input is only as accurate and reli‐
able as the method with which the data was deter‐
mined.
The sensor data must have been determined
recently. The more up-to-date the sensor data, the
more reliable is this calibration method.
Correct sensor operation
–
Correct measuring and metering is only pos‐
sible if the sensor is working perfectly.
–
Refer to the sensor's operating instructions.
Measuring and control behaviour of the controller
during calibration
During calibration the actuating outputs are deacti‐
vated. Exception: a basic load or a manual control
variable has been set. This remains active. The
measured value output [standard signal output mA]
is frozen, corresponding to its settings in the mA
output menu.
When calibration/testing has been completed suc‐
cessfully, all of the error checks relating to the
measured value are restarted. The controller saves
all the determined data for zero point and slope
upon a successful calibration.
Tab. 9: Valid calibration values
Evaluation Zero point Slope
Good -30 mV … +30 mV -55 mV/pH ... -62 mV/pH
Acceptable -60 mV ... -30 mV
or +30 mV ... +60 mV - 40 mV/pH ... - 65 mV/pH
Continuous display ➨
Calibrating the controller diaLog DACb
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