FISCHER NC56, Operating Manual, Page: 8 / 24

2 | Product and functional description FISCHER Mess- und Regeltechnik GmbH
8/24 BA_EN_NC56
2.4 Function diagram
C
E
C
A
C
A
: Start capacity (probe free)
C
E
: End capacity (probe covered)
RxD
Min.
Max.
+U
b
-U
b
Output
brown
blue
black
IR
Status LED
Probe
µC
Fig. 4: Function diagram
2.5 Design and mode of operation
An AC voltage signal is exerted onto two metal rods held at a defined distance
to each other. This means that the metal rods become a capacitor when dipped
into fluids. The capacitive values of this capacitor are primarily determined via
the filling level height and the resulting change in the dielectrics.
Electronics integrated into the device convert these capacity changes into linear
uniform electrical signals. A comparison is conducted with an infrared remote
control.