Calibrating The Parameters Cl - Grundfos AQC-D12 Installation And Operating Instructions Manual

10.7.1 Setting the quantity of sample water
A correct measurement can only be taken, if the quantity of
sample water is within a defined range. This range is from 200 to
800 rotations/minute of the cleaning wing.
• Set the quantity of sample water with the regulation (G) so that
the measuring amplifier shows a sample water flow rate of 200
to 800 rotations/minute. The bar in the display of the
measuring amplifier shows the range. The exact speed can be
taken from the service menu.

10.8 Calibrating the parameters Cl

At first start-up or after long-term stop: Let the
Caution
system run for at least two hours to avoid faulty
measurements and calibration!
Due to the electro-chemical behaviour of the measuring cell, no
zero-point adjustment is necessary. Only the rate of rise
(sensitivity) must be adjusted during calibration.
During calibration: Keep pH value, sample water flow
Caution
rate and water temperature constant.
• Check the calibration after 24 hours. Repeat, if necessary.
10.8.1 Photometrical determination of a reference value
1. Open the sampling cock (I), and let the water run for a few
seconds.
2. Take a water sample, and close the sampling cock.
3. Determine the concentration of the measuring parameter
photometrically, for instance using the Grundfos DIT hand
photometer.
4. Keep this value as a reference value.
Observe the installation and operating instructions of
Caution
the photometer!
16
, ClO , O
2 2 3
10.8.2 Calibration example based on chlorine measurement
with pH compensation (not with Conex DIS-D)
Observe the installation and operating instructions of
Caution
the measuring amplifier and controller!
• Define the basic settings for the measuring amplifier.
When carrying out a chlorine measurement with pH
compensation, the pH value must be calibrated first,
Note
since the pH value is used when calibrating the
chlorine value!
Calibrating the pH value
• DIP: Push the button underneath the right-hand display.
• Conex DIA and DIP: Use the [CAL] button to select the
calibration function CAL. The LED illuminates.
1. If necessary, enter the code number for CAL (or full)
authorisation.
2. Change to the menu "calibration" with the [OK] button.
3. Select the measured variable "pH", and confirm with [OK].
– Selection possibilities: "cal. meas. value" (= measured
value), "cal. result" and "cal. cycle" (= count-down function
which triggers the alarm "calibrate sensor" after a selectable
time interval of 1-100 days).
4. Select the line "cal. meas. value" with [UP]/[DOWN].
pH
cal. meas. value
cal. result
cal. cycle
5. Select one of the defined buffer solutions ("GRUNDFOS",
"DIN/NIST", "others"), and press [OK].
– The menu "temperature" is selected automatically.
buffer
GRUNDFOS
DIN/NIST
others
6. Enter the temperature of the buffer solutions.
7. Press [OK] to jump to the menu "buffer value 1".
8. "GRUNDFOS" or "DIN/NIST" buffer solutions: Select one of
the available buffer values.
buffer value 1
4.01 pH
7.00 pH
9.18 pH