Pr
o
Minent
®
Page 131
pH/Chlorine Dioxide
8.11.2.3
DULCOTEST
®
CDE Chlorine Dioxide Sensor and DULCOTEST
®
Sensor
PHEP or PHER for pH, Running-In
Running-In
DULCOTEST
®
CDE Chlorine Dioxide Sensor
IMPORTANT
• The sensor must be used only in surfactant-free water or solutions!
• When operating the sensor, the sample water must permanently contain chlorine
dioxide.
• Do not switch off the measuring system during interval operation! After operation
without chlorine dioxide, running-in periods are to be reckoned with. If required, switch
on metering unit time-delayed! If no chlorine dioxide is metered for a longer period of
time, the sensor must be disconnected from the power supply and stored dry.
Running-In
Period
The sensor requires a run-in period before it will display stable readings.
Commissioning:
2 - 6 h
Re-commissioning:
1 - 3 h
Diaphragm-/electrolyte replacement: approx. 0.5 h
pH
Sensor
The
DULCOTEST
®
PHEP or PHER sensor for pH must not be run-in. The DULCOTEST
®
PHEP or
PHER sensor for pH can be readily used.
8.11.2.4
DULCOTEST
®
CDE Chlorine Dioxide Sensor and DULCOTEST
®
Sensor
PHEP or PHER for pH, Calibration
Calibration
DULCOTEST
®
CDE Chlorine Dioxide Sensor
The sensor can be calibrated after the run-in period.
IMPORTANT
• A slope test must be carried out after replacing the diaphragm cap or electrolyte!
• Slope tests must be carried out at regular intervals to ensure correct functioning of the
sensor! For testing drinking water, calibration of the sensor every 3 - 4 weeks is suffi ci-
ent.
• Avoid incorrect dosing due to air bubbles in the water. Air bubbles clinging to the sensor
diaphragm can reduce the measured variable and thereby lead to overdosing.
• Observe applicable national directives for calibration intervals!
Preconditions
• Constant
fl ow to the in-line probe housing.
• Constant sample water temperature.
• Same sample water and sensor temperatures (wait approx. 15 min.).
Zero Point Calibration
If a ProMinent controller is being used to operate the sensor there is no need for zero point
calibration. Zero point calibration should be carried out, however, if operating the sensor in the
lower measurement range, or if using the 0.5 ppm variant.
Preconditions
• The sensor has been run in.
• Flow to the in-line probe housing is constant and complies with technical data.
Insert the sensor into a container of clean, ozone- and ClO
2
-free water.
Stir with the sensor until the measured variable displayed at the controller has remained stable
for 5 min.
Calibrate the controller to zero in accordance with the operating instructions.
Replace sensor into the in-line probe housing (DGM; DLG).
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