Grundfos Oxiperm Pro OCD-162-10, Installation And Operating Instructions Manual

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Reading the slope in the calibration logbook
1. SERVICE > MEASUREMENT > [OK].
2. ClO
2
> [OK].
3. CALDATA/LOGBOOK > [OK].
Entry no. 1 is the latest entry, entry no. 2 is the previous one, etc.
Enabling/disabling the display of the ClO
2
calibration interval
1. CALIBRATION > ClO
2
> CAL. CYCLE > [OK].
2. (Interval) OFF > [OK] or
3. (Interval) ON > [OK].
5.13.2 Performing (two-point) pH calibration
The electrode sends the voltage (in mV), that corresponds to
the pH value, to the control system.
Two different buffer solutions can be used to calibrate the pH
measured value.
1. Prepare two glass jars with the buffer solutions.
2. Have an empty 10-litre plastic bucket ready.
3. Measure the temperature of the buffer solution (using a
thermometer).
4. Press [Cal].
5. pH > [OK].
6. CAL. MEAS. VALUE > [OK].
7. Use the [Up] or [Down] button to select one of the three buffer
types.
8. GRUNDFOS > [OK].
9. Set the measured temperature of the buffer solution in the
display > [OK].
10. Shut off the measuring cell water supply.
11. Unscrew the pH electrode from the measuring cell. Use the
bucket to catch any water that runs out. See the end of the
section
Alternative method using the calibration lute
).
12. Immerse the pH electrode in one of the glass jars containing
the buffer solution, for example 4.01 pH.
13. In the display, select the buffer value of the buffer solution in
which the electrode is immersed, for example 4.01 pH > [OK].
The voltage in mV at the electrode in the buffer solution (for
example
4.01 pH) is measured and assigned to the pH value.
14. Remove the pH electrode from the buffer solution, and rinse
with water.
15. Immerse the pH electrode in the glass jar containing the
second buffer solution, for example 7.00 pH.
16. Select the buffer value of the buffer solution in which the
electrode is immersed, for example 7.00 pH.
The voltage in mV at the electrode in the second buffer solution
(for example 7.00 pH) is measured and assigned to the pH value.
The result is represented geometrically:
When the voltage (mV) is represented on the y axis and the pH
value on the x axis, the result is two points. Joining the two points
results in a straight line.
17. CAL. RESULT > [OK].
The result is displayed as the slope of the straight line, and the
asymmetry (the asymmetry is the deviation from the zero
point at
pH 7). In this example, one pH unit corresponds to –57.88 mV.
18. Remove the pH electrode from the buffer solution, and rinse
with water.
19. Screw the pH electrode back into the measuring cell.
The current pH value of the water in the main water line is
updated in the display level.
20. Turn the measuring cell water supply back on.
21. Dispose of the buffer solution. Do not pour it back into the
bottle.
22. Pour the contents of the bucket down the drain.
pH calibration has been completed.
CALDATA/LOGBOOK
NO. ..................................1
DATE ................31.07.2007
TIME .........................12:34
SLOPE ...................22.0 µA
CALIBRATION
CHLORINE DIOXIDE
pH/REDOX
pH
CAL. MEAS. VALUE
CAL. RESULT
CAL. CYCLE
CAL. MEAS. VALUE
GRUNDFOS
DIN/NIST
OTHER
Buffer type Buffer values
GRUNDFOS 4.01, 7.00, 9.18
DIN/NIST 4.01, 6.86, 9.18
OTHER
The lower and upper buffer values can be
freely adjusted (difference of at least 1 pH)
within the set pH measuring range.
BUFFER TEMPERATURE
25 °C
BUFFER VALUE
4.01 pH
7.00 pH
9.18 pH
CAL
Please wait
BUFFER VALUE
4.01 pH
7.00 pH
9.18 pH
CAL
Please wait
CAL. RESULT
SLOPE
-57.88 mV/pH
ASYM.
-0.6 mV
PROCESS RUNNING
21 °C
0.24 mg/l
7.00 pH