Construction And Function - ProMinent DULCOTEST CLT 1-mA-2 ppm Montage- Und Betriebsanleitung

Construction and Function

Construction
The CLT 1 sensor consists of 3 main parts, the
top part, the electrode shaft and the diaphragm
cap. The electrolyte-filled diaphragm cap con‐
stitutes the measuring chamber, into which the
measuring electrodes are immersed. The
measuring chamber is sealed from the meas‐
uring medium by a micro-porous diaphragm.
The amplifier electronics, embedded into a
plastic mass, are located in the top part of the
shaft. The sensor has a passive 4 ... 20 mA
two-wire interface. The power supply is external
from the controller.
2.2 Function
The CLT 1 sensor is a diaphragm-covered,
amperometric two-electrode sensor. A gold
anode acts as a working electrode and a silver
halide-coated cathode acts as a counter and
reference electrode. The chlorite contained in
the sample water diffuses through the dia‐
phragm. The constant polarisation voltage
between the two electrodes produces the elec‐
trochemical reaction of the chlorite on the
working electrode. The resulting current is
measured as a primary signal (amperometric
measuring principle). It falls within the operating
range of the sensor in proportion to the concen‐
tration of chlorite and is negligibly dependent
on the pH in this sensor type. The primary
signal is converted into a temperature-cor‐
rected 4 ... 20 mA output signal by the amplifier
electronics of the sensor and displayed and
processed in the measuring/control device.
The measuring signal of the CLT sensor follows
the value determined by the DPD. This makes
it possible to determine the chlorite content.
14