8.5 Help texts
Content of the help
texts
Cause
Remedy
The DPD value is too
small, DPD value >
MRS + 2 %
If the calculated reference value (e.g.
DPD1) for calibrating a sensor is less
than 2 % of the measuring range, then
calibration is not possible.
Increase the concentration of the chem‐
ical to be measured in the process/
sample water and determine the refer‐
ence value again (e.g. DPD1) after the
run-in period.
The slope is too
shallow, < 20 % of the
MR
The sensor can no longer detect the
chemicals to be measured
Replace the membrane cap and replace
the electrolyte for new material
The slope is too steep,
> 300 % of the MR
The sensor has been permanently
affected by for example surface-active
substances (surfactants).
Make sure that none of these sub‐
stances are present in the water.
Replace the membrane cap and replace
the electrolyte for new material
The zero point is too
low, < 3.2 mA
The sensor delivers a measured signal
that is less than 3.2 mA. This value is
outside of the specification.
Check the raw value in mA in the Infor‐
mation menu, by pressing in the main
display. If the value is < 3.2 mA, then
this is not the correct sensor signal.
Check the cabling and replace the
sensor with a new sensor.
The zero point is too
high, > 5 mA
You would like to calibrate the zero
point but the sensor is still detecting
the chemical to be measured
Rinse the sensor with water containing
no chemicals that are to be measured
before zero point calibration. The water
with which the zero point is determined
should also not contain traces of this
chemical. Use mineral water without
carbon dioxide for this purpose.
An unknown calibration
error
In the residual period
parameter set 1 is used
If parameter set 2 is not active, then
parameter set 1 is activated
Check the control signals/lines that
switch the parameter set or check the
timer settings.
[Diagnostics]
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