10.3 Calibrating the Sensors
All sensors are calibrated, as described in the operating instruc‐
tions for the controllers and sensors fitted. Any sample required is
taken at the sampling points labelled on the measuring plate, see
Chapter 10.2 ‘Sampling from the Bypass Fitting’ on page 49.
10.4 Calibrating the Fluoride Sensor
There is a fundamental distinction between 1-point calibration and
2-point calibration. 1-point calibration is performed using a
standard solution with e.g. 1 ppm fluoride for calibration. 2-point
calibration is performed using two standard solutions, which have
to be more than 1 ppm apart (minimum value 0.5 ppm).
There are two options for calibrating a fluoride sensor:
n
Calibration with a photometer DT2C (order number: 1039316)
n
Calibration with a standard solution
The fluoride sensor is calibrated, as described in the operating
instructions for the controller and sensors fitted.
Refer to the operating instructions for the photometer DT2C.
Calibration instructions
Regularly check and calibrate the sensor.
Please note the applicable national guidelines.
The sensor needs to have run in prior to initial cali‐
bration.
Observe the controller operating instructions.
Perform 2-point calibration during initial commis‐
sioning.
2-point calibration needs to be carried out less reg‐
ularly than 1-point calibration.
The standard solution has to be evenly stirred with a magnetic
stirrer during calibration.
Use a standard solution with a conductivity of
> 1000 μS/cm(e.g. 1g/litre Na
2
SO
4
solution) to accelerate potential
adjustment. The two standard solutions have to be more than 1
ppm apart (minimum value 0.5 ppm) to calibrate the slope (2-point
calibration).
1.
Immerse the sensor, the reference electrode and the Pt 100
(if fitted) into the standard solution for calibration
2.
Perform calibration in line with the controller's specification,
referring to the operating instructions for the controller.
Calibration with a photometer DT2C
Calibration with a standard solution
Starting-up Sensors
50
Summary of Contents for DULCOTROL DWCa
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