Description Of The Device; Assembly; Principles Of Conductivity Measurement - Grundfos Conex DIS-C Montage- Und Betriebsanleitung

3. Description of the device

®
Conex DIS-C for wall mounting
Fig. 1
®
Conex DIS-C for installation in control
Fig. 2
panel

3.1 Assembly

The complete measuring system comprises:
• the measuring amplifier Conex
• the conductivity measuring cell with temperature
sensor.
3.2 Principles of conductivity
In metallic conductors, electricity is transported by
freely moving electrons, whereas in electrolytes, the
electrical current is carried by ions.
All water-dissolved components that are in ionogenic
form contribute towards conductivity.
The conductivity is a sum parameter.
Different types of ions vary in their electrical charge
and migration rate. The migration rate is highly
dependent on temperature, which means the
influence of temperature must always be taken into
account when measuring conductivity.
Specific electrolytic conductivity is measured in
Siemens per cm (S/cm). Siemens per cm is the
reciprocal value of electrical resistance.
This measurement is based on a theoretical liquid
cube with sides of a length of 1 cm. In practice, cells
rarely have such an even geometric shape. The cell
constant C is used to specify the correlation between
the actual measured conductivity and the displayed
specific conductivity.
The measuring cell is inserted in a flow armature,
and the water to be measured flows around it.
The Conex
amplifies the signal from the measuring cell and
calculates the signal (e.g. against cable and
temperature compensation parameters). The result
is displayed digitally and can also be registered
using the analog output. The result is shown as an
actual value.
®
DIS-C
measurement
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DIS-C measuring and regulation device
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