Calibration Errors - Bayrol PoolManager Chlorine User Manual

13
Using the measured value, you can see when measurement stabilises
when you, for example, place the electrode into the buffer solution.
Current Signal
This is the currently measured electric signal on the electrode in [mV].
You can also use the measurement signal to see when measurement
has stabilised.
Furthermore, you can use it to check the measurement signal for
plausibility.
pH value 6.0 6.5
Typical +60 mV +30 mV
measurement
signal
Tolerance to be expected ±10%
Electrode (for 1-point calibration only)
For 1-point calibration, the electrode slope is also displayed in [mV/pH]
and can be edited manually. This makes it possible for you to enter a
typical value for slope, or to reset slope to its default value.
For 2-point calibration, slope cannot be entered manually as it is
calculated exactly during calibration.
13.2.1.2 Calibration results
At the end of calibration, the calibration parameters calculated are
displayed:
Electrode slope
For 2-point calibration, this is the newly calculated electrode slope in
[mV/pH]; for 1-point calibration this is the previously entered value.
Offset
Offset is the zero point shift calculated by calibration. Indicated in [pH].
Current value
The pH measured value is now calculated using the parameters from
the current calibration. The measured value displayed should therefore
be consistent with the calibration value entered.
13.2.1.3 Step by step
1-point calibration with buffer solution (e.g. pH 7)
1. Block the measuring water
2. Separate the electrode cable from the controller
3. Unscrew the pH electrode from the measurement chamber
4. Rinse the pH electrode off with (distilled) water
5. Carefully dab the pH electrode dry using a cloth (free from
grease and fluff).
6. Connect the electrode cable to the controller again.
7. In the menu, select the function 1-point calibration pH
8. Enter the pH value of the buffer solution as the calibration value
(typically pH 7)
9. If necessary, enter a value for electrode slope or reset the value
to default
10. Dip the pH electrode into the buffer solution (e.g. pH 7) and stir
it carefully and briefly
11. If the displayed measured value and the measurement signal
have stabilised and are no longer changing in a relevant
manner, then confirm calibration by pressing Next.
12. Check the calibration results displayed and close calibration by
pressing Ready.
13. Place the pH electrode back into the measurement chamber
14. Open the shut-off valves for measuring water
34
7.0 7.5 8.0 8.5
0 mV -30 mV -60 mV -90 mV
2-point calibration with buffer solution (e.g. pH 9 and pH 7)
1. Block the measuring water
2. Separate the electrode cable from the controller
3. Unscrew the pH electrode from the measurement chamber
4. Rinse the pH electrode off with (distilled) water
5. Carefully dab the pH electrode dry using a cloth (free from
grease and fluff).
6. Connect the electrode cable to the controller again.
7. In the menu, select the function 2-point calibration pH
8. Enter the pH value of the 1st buffer solution as the 1st
calibration value (pH 9)
9. Dip the pH electrode into the 1st buffer solution
(pH 9) and stir carefully and briefly
10. If the measured value displayed and the measurement signal
have stabilized and are no longer changing in a relevant
manner, then confirm the 1st calibration point by pressing Next.
11. Remove the pH electrode from the 1st buffer solution
12. Rinse the pH electrode off with (distilled) water
13. Carefully dab the pH electrode dry using a cloth (free from
grease and fluff).
14. Enter the pH value of the 2nd buffer solution as the 2nd
calibration value (pH 7)
15. Dip the pH electrode into the 2nd buffer solution
(pH 7) and stir carefully
16. If the measured value displayed and the measurement signal
have stabilised and are no longer changing in a relevant
manner, then confirm the 2nd calibration point by pressing Next.
17. Check the calibration results displayed and close calibration by
pressing Ready.
18. Place the pH electrode back into the measurement chamber
19. Open the shut-off valves for the measuring water
1-point calibration to the pool water's pH value
1. Take a water sample from the measurement chamber and
measure the pH value using a photometer
(phenol red method).
2. In the menu, select the function 1-point calibration pH
3. Enter the pool water's pH value measured using the photometer
as the calibration value
4. If necessary, enter a value for electrode slope or reset the value
to default
5. If the measured value displayed and the Current Signal pH are
stable and are no longer changing in a relevant manner, then
confirm calibration by pressing Next.
6. Check the calibration results displayed and close calibration by
pressing Ready.
13.2.2

Calibration errors

During calibration, various plausibility criteria are checked. If one of the
criteria is not met, then a corresponding error message appears and
calibration is not executed.
The following criteria have to be met for successful calibration:
The offset calculated (zero point shift) has to be in the range of ±1.00
pH. The offset is generally close to 0 for flawless electrodes.
The electrode slope calculated must be in the range of 50.0 mV/pH to
70.0 mV/pH. For flawless electrodes, the slope is generally between
55.0 mV/pH and 60.0 mV/pH.
For 2-point calibration, the two calibration values have to be at least
0.50 pH apart. 2-point calibration with buffer solutions pH 7 and pH
6.80, for example, is not possible.