Error description:
Sensor display >> DPD 1 value,
No calibration possible (gradient too high)
Measure/Remedy
1.
Check whether there is additional
oxidising agent (e.g ozone, chlorine
dioxide, or chloramines) in the sample
water
ð
Remove them. If this is not possible
then contact ProMinent.
2.
Check the age of your DPD chemicals
ð
If there is doubt, repeat the DPD
measurement with new chemicals
and then re-calibrate.
3.
When directly connecting the sensor to
external devices (e.g. PLC), make sure
that the sensor is galvanically isolated
from all other devices/consumers
ð
Always use a separating transformer
for the supply.
4.
Foreign (stray) potentials on the water
(e.g. due to defective rotary pump)
5.
If the reason for this disturbance cannot
be determined we recommend you clean
the sensor as described in
Error description:
Sensor display fluctuates
Fluctuation due to system
Repeat the DPD measurement at short
intervals and thereby exclude that the
sensor fluctuations are not caused by the
system.
Measure/Remedy
1.
Check that there is a constant flow rate at
the sensor of at least 30 l/h .
2.
Make sure that there is a sufficient mixing
distance after metering the chlorine .
ð
If necessary, install a static mixer.
3.
When directly connecting the sensor to
external devices (e.g. PLC), make sure
that the sensor is galvanically isolated
from all other devices/consumers
ð
Always use a separating transformer
for the supply.
4.
Foreign (stray) potentials on the water
(e.g. due to defective rotary pump)
Troubleshooting
28
