12
Calibration (basic measurement comparison)
TIP
pH calibration
Precise calculation can be attained with the following
procedure:
Basic calibration step 1
2-point calibration with buffer solutions pH 7 and
pH 9 in order to calculate the exact electrode slope.
Basic calibration step 2
Subsequent 1-point calibration to the pool's pH value
with a photometer in order to attain the best
concordance possible between the device's display and
the photometer measurement.
This calibration should be performed as close to the
setpoint as possible, i.e. the pH value in the pool
should be in the ideal range between 7.0 and 7.4
If there is no photometer avail
should be performed. A simple colour tester does not
produce reliable calibration with the requisite precision.
Recalibration
1-point calibration generally suffices for regular
recalibration (at least once a month). If there is a
photometer available, then recalibration should be
performed to the pool's pH value; otherwise with buffer
solution pH 7.
12.2.1
Execution
pH calibration can be found in the following menu:
C
alibration pH
Calibration is executed as follows:
•
Select 1-point calibration pH or 2-point calibration pH
•
Calibration is a menu sequence, i.e. it goes through a series of
menus step-by-step.
12.2.1.1
Calibration input (1st and 2nd calibration point)
In the input menus for the 1st and 2nd calibration point, the following
parameters are displayed:
Calibration value pH
For the calibration value, enter the reference value to which calibration
should be performed.
When calibrating with a buffer solution, this will be the known pH value
of the buffer solution, such as pH 7 or pH 9.
When calibrating to the pool water's pH value, this will be the value
measured with a photometer (a simple colour tester is not suitable for
calibration as the measurement precision is not sufficient).
Current value pH
This is the current measured value calculated using the parameters
from the last calibration, which are still valid. This value may deviate
from the actual value under certain circumstances. It is only displayed
to give you a certain level of orientation throughout calibration.
Using the measured value, you can see when measurement stablises
when you, for example, place the electrode into the buffer solution.
Current signal pH
This is the currently measured electric signal on the electrode in [mV].
You can also use the measurement signal to see when measurement
has stablised.
Furthermore, you can use it to test the measurement signal for
plausibility.
Calibration (basic measurement comparison)
User Manual PoolManager
®
Precise calculation can be attained with the following
point calibration with buffer solutions pH 7 and
pH 9 in order to calculate the exact electrode slope.
point calibration to the pool's pH value
with a photometer in order to attain the best
possible between the device's display and
This calibration should be performed as close to the
setpoint as possible, i.e. the pH value in the pool
should be in the ideal range between 7.0 and 7.4
If there is no photometer available, then only step 1
should be performed. A simple colour tester does not
produce reliable calibration with the requisite precision.
point calibration generally suffices for regular
recalibration (at least once a month). If there is a
tometer available, then recalibration should be
performed to the pool's pH value; otherwise with buffer
pH calibration can be found in the following menu:
point calibration pH
Calibration is a menu sequence, i.e. it goes through a series of
Calibration input (1st and 2nd calibration point)
In the input menus for the 1st and 2nd calibration point, the following
For the calibration value, enter the reference value to which calibration
When calibrating with a buffer solution, this will be the known pH value
n calibrating to the pool water's pH value, this will be the value
measured with a photometer (a simple colour tester is not suitable for
calibration as the measurement precision is not sufficient).
calculated using the parameters
from the last calibration, which are still valid. This value may deviate
from the actual value under certain circumstances. It is only displayed
to give you a certain level of orientation throughout calibration.
asured value, you can see when measurement stablises
when you, for example, place the electrode into the buffer solution.
This is the currently measured electric signal on the electrode in [mV].
see when measurement
Furthermore, you can use it to test the measurement signal for
pH value
6.0
6.5
Typical
measurement
signal
+60
mV
+30
mV
Tolerance to be expected ±10%
pH Electrode slope (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 as it is calculated
exactly during calibration.
12.2.1.2
Calibration results
At the end of calibration, the calibration parameters generated are
displayed:
Electrode slope
For 2-point calibration, this is the newly
[mV/pH]; for 1-point calibration this is the previously entered value.
Offset
Offset is the zero point displacement calculated from calibration. It is
indicated in [pH].
Current value pH
The pH measured value is then calculate
the current calibration. The measured value displayed should therefore
coincide with the calibration value entered.
12.2.1.3
Step by step
1-point calibration with buffer solution (e.g. pH 7)
1.
Block the measurement water
2.
Separate the electrode cable from the device
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 towel (free from
grease and fuzz).
6.
Connect the electrode cable to the device
7.
In the menu, select the function
8.
Enter the pH value of the buffer solution as the
(generally pH 7)
9.
If necessary, enter a value for electrode slope or reset the value
to default
10.
Dip the pH electrode into the b
it carefully
11.
If the displayed measured value and the measurement signal
have stablised and are no longer changing in a relevant
manner, then confirm calibration by pressing
12.
Check the calibration results displayed a
pressing
Ready.
13.
Place the pH electrode back into the measurement chamber
14.
Open the shut-off valves for measurement water
34
7.0
7.5
8.0
8.5
+30
0 mV
-30 mV -60 mV -90 mV
point calibration only)
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.
point calibration, slope cannot be entered as it is calculated
At the end of calibration, the calibration parameters generated are
point calibration, this is the newly calculated electrode slop in
point calibration this is the previously entered value.
Offset is the zero point displacement calculated from calibration. It is
The pH measured value is then calculated using the parameters from
the current calibration. The measured value displayed should therefore
coincide with the calibration value entered.
point calibration with buffer solution (e.g. pH 7)
Block the measurement water
rode cable from the device
Unscrew the pH electrode from the measurement chamber
Rinse the pH electrode off with (distilled) water
Carefully dab the pH electrode dry using a towel (free from
Connect the electrode cable to the device again.
In the menu, select the function
1-point calibration pH
Enter the pH value of the buffer solution as the
calibration value
If necessary, enter a value for electrode slope or reset the value
Dip the pH electrode into the buffer solution (e.g. pH 7) and stir
If the displayed measured value and the measurement signal
have stablised and are no longer changing in a relevant
manner, then confirm calibration by pressing
Next.
Check the calibration results displayed and close calibration by
Place the pH electrode back into the measurement chamber
off valves for measurement water