Calibration Of Amperometric Sensors; Selecting The Calibration Process For Amperometric Measured Variables - ProMinent DULCOMETER diaLog DACb Assembly And Operating Instruction

10.4 Calibration of Ampero‐
metric Sensors
Calibration of Amperometric Sen‐
sors
The calibration procedure for ampero‐
metric sensors is the same for all
amperometric measured variables.
The procedure for calibrating ampero‐
metric measured variables is described
throughout based on the measured var‐
iable chlorine [Cl]. All other measured
variables require the same procedure
as the measured variable chlorine [Cl].
The following measured variables can
be calibrated using the procedure
described here:
Chlorine
–
Chlorine dioxide
–
Bromine
–
Chlorite
–
Ozone
–
Peracetic acid (PES)
–
H O
–
2 2
Combined calibration of pH and
chlorine
It is mandatory that the pH measure‐
ment is always calibrated first and then
the chlorine measurement. All other
calibration of the pH measurement
must always be followed by calibration
of the chlorine measurement. Other‐
wise the chlorine measurement will be
inaccurate.
Free chlorine or total available
chlorine
Calibration of the zero point is not nec‐
essary.
Slope: Possible calibration in the range:
20% ... 300%.
A slope below 70% indicates a
blockage of the diaphragm. Refer to the
operating instructions for your sensor.
A slope of over 150% with sensors
CLE3/CLE1 indicates surface-active
components (surfactants) in the sample
water. Replacing the diaphragm only
delivers short-term improvement. It is
important to prevent the occurrence of
surfactants in the water. If surfactants
cannot be avoided, then use an appro‐
priate sensor, for example sensor type
CBR.
10.4.1 Selecting the calibration
process for amperometric
measured variables
There are two calibration processes available
for calibrating the controller:
Calibrating the slope
n
Calibrating the zero point
n
Calibration
103