Cable break detection
[ON]
/
[OFF]
: Switches cable break detec‐
tion of the coaxial cable
[ON]
or
[OFF]
.
The factory setting is
[OFF]
. If the con‐
troller has the setting
[ON]
, it displays an
alarm message if an error is detected.
The cable break detection device monitors
a pH sensor with a coaxial connection
cable to determine whether a break exists
in the coaxial connection cable. If a break
exists in the coaxial connection cable, the
resistance increases enormously to
approximately 1 giga-Ω. The controller
can interpret this resistance change. The
controller generates an error message
and control is stopped. This error cannot
be acknowledged.
The glass membrane of the pH sensor
becomes highly resistant when the
process temperature falls. Once the
process temperature is approx. < 15 °C
the detection threshold of 1 gig-Ω is
reached. For process temperatures
< 15 °C a cable break is detected even
though no cable break exists. So that an
error alarm is avoided, cable break detec‐
tion must be switched off at process tem‐
peratures < 15 °C.
Measuring range of the measuring trans‐
ducer
Select the measuring range. The meas‐
uring range is printed on the nameplate of
the measuring transducer. An incorrect
measuring range will lead to an incorrect
measurement.
Measuring range of the sensors
Select the measuring range. The meas‐
uring range is given on the sensor name‐
plate. An incorrect measuring range leads
to an incorrect measurement.
Measured variable chlorine, bromine,
chlorine dioxide, chlorite, dissolved
oxygen and ozone:
The measured variables chlorine , bro‐
mine, chlorine dioxide, chlorite, dissolved
oxygen and ozone are always measured
using a mA signal because the measuring
transducer is located in the sensor.
The temperature compensation takes
place automatically inside the sensor
(exception: CDP, chlorine dioxide sensor).
For further information see the operating
instructions of the sensor used.
Measured variable conductivity [mA]
When measuring conductivity [mA], use of
a measuring transducer is a prerequisite,
e.g. a measuring transducer DMTa con‐
ductivity. A conductivity sensor cannot be
directly connected to the controller.
Measuring range:
n Select the measuring range corre‐
sponding to the measuring range of
the measuring transducer used. An
incorrect measuring range leads to an
incorrect measurement.
Temperature:
n The temperature measurement is
used only for information or recording
purposes, but not however for tem‐
perature compensation. Temperature
compensation is carried out in the
measuring transducer.
Glossary
170
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