Operation; Function - Grundfos AQC-D13 Montage- Und Betriebsanleitung

10.8.3 Calibrating the parameters chlorine, chlorine dioxide
or ozone with Conex DIS-D
1. Press the [CAL] button to select the calibration menu.
– The CAL LED next to the [CAL] button illuminates.
– The display shows the current measured value.
– To prevent overdosing, the controllers must be switched off,
and the device controlled must be closed.
2. Use [UP]/[DOWN] to select the reference value.
3. Start the calibration with [OK].
– The sensor data are then read in.
– The slope (sensitivity) of the sensor is calculated.
– The calibration result is displayed immediately after
calibration.
– The sensor slope is displayed in µA/ppm.
Calibration result
• The result of the current (last) calibration can be displayed in
the code menu at any time:
– Code 51: display of calibrated slope in µA/ppm.
Error message when reading in the current signal of the
sensor system
• The alarm LED flashes.
• The display shows code *13* (slope error).
The alarm is triggered, if the plausibility check results in an
upward or a downward violation of the following slope ranges,
depending on the selected measuring cell:
Measuring cell Lower limit
AQC-D13 2.5 µA/ppm
• Press [OK] to acknowledge the error message and to return to
the display level.
– The calibration data are imported.
The controller is operating in emergency mode!
Eliminate the fault, see section
Note
and calibrate again!

11. Operation

11.1 Function

Various oxidation agents are used for the disinfection of
swimming-pool water and drinking water, for instance chlorine
(Cl
It is necessary to measure the concentration of the oxidation
agent and to regulate its dosing.
•
•
The AQC-D13 measuring cell is used for measuring the
concentration of chlorine (Cl
(O
3
and redox electrodes, and also for a water sensor and an Pt100
temperature sensor.
Preassembled system with Conex DIA, Conex DIS and DIP are
used when the values of decontamination agents, pH and
redox-potential have to be determined and controlled. The basic
element of the preassembled systems is the AQC-D13 measuring
cell.
11.1.1 Functional principle of measurement
•
Upper limit
70.0 µA/ppm
11.5 Fault finding, •
•
•
11.1.2 Electrode cleaning
The measuring electrode and the counter-electrode are
continuously cleaned of deposits by a cleaning wing.
•
•
), chlorine dioxide (ClO ) and ozone (O
2 2
Concentration of oxidation agent is too low:
– Disinfection effect is too weak.
Concentration of oxidation agent is too high:
– Danger to health
– Unpleasant odour and taste
– Corrosion damage
– Increased operating costs.
), chlorine dioxide (ClO
2
) and is equipped with additional holders for pH electrodes
Sample water is taken at a representative position and passed
to the measuring cell via an integral filter.
– The water flow rate can be adjusted on the measuring cell.
– A water sensor (optional) serves to trigger an alarm or to
switch off the control function, if there is a sample water
deficiency.
– The agent to be determined (Cl
the gold or platinum electrode.
The agent to be determined generates an electric current in
the µA range, proportional to its concentration.
– The measuring cell is controlled by a potentiostat in the
measuring amplifier.
A constant voltage is applied to the measuring electrode.
An exactly defined potential of the measuring electrode is
retained by means of the reference electrode. This results in a
linear response for the measuring cell as well as a stable zero
point for the measurement.
The Conex or DIP measuring amplifiers and controllers
– amplify the current
– calculate it using the calibration parameters
– display the concentration as a digital value
– control a gas dosing unit or a dosing pump
(device controlled).
This ensures uniform sensitivity for the measuring cell over a
long period.
The cleaning wing is driven hydraulically.
).
3
) or ozone
2
, ClO or O ) is measured at
2 2 3
17