fafnir CONDURIX DU, Техническая документация инструкция

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Design and function Page 4/ 20
The fill level is calculated from the ratio of the measured voltages by a microcontroller.
The ratio of the two voltages also enables the orientation of the CONDURIX sensor to be
detected, i.e. whether the sensor has been installed from top down or bottom up.
The level sensor is fed from a 2 - wire 4 … 20 mA interface and requires a voltage of
between 8 and 30 V. The position of 4 mA and 20 mA points on the probe tube is freely
adjustable (see chapter
6, Parametrisation). To prevent galvanic processes from occurring
in the liquid, both the discharging and charging currents flow through a galvanically
isolating transformer. The alternating voltage produced across the very low - resistance
probe tube is in the 100 mV range.
The table below shows the signal characteristics of the sensor as a function of sensor ori-
entation and the measured value output setting (normal/inverted).
Measured value output
normal
Measured value output
inverted
Filling level “Empty” sig-
nal
Filling level “Empty” sig-
nal
Installation
top down
3.8 mA 20.5 mA
Installation
bottom up
3.8 mA 20.5 mA
Figure 2: Measured value output
Installation top down: The zero point is at the probe base
Installation bottom up:
The zero point is at the sensor head
Normal measured value output: The 20 mA point is higher than the 4 mA point
Inverted measured value output: The 20 mA point is lower than the 4 mA point
20 mA
4 mA
4 mA
20 mA
20 mA
4 mA
4 mA
20 mA