Operating Instructions MBI 46.51.39
Version 0.9
en MBI 46.51.39 operating instructions.docx
Issue: 08/2022
page 9 from 29
The electrical design of the three displacement transducer types offered by MESSOTRON is
described below.
4.3.1 Linear Variable Inductive Transducers (LVIT)
Electrically, a displacement transducer based on the differential inductor principle represents
a Wheatstone half-bridge consisting of two measuring coils. The core, which moves inside the
coils, causes in its middle position (electrical zero point) that both measuring coils have the
same impedance. The bridge circuit is thus balanced, the measuring voltage is zero.
Figure 1
Amplifier with Differential Choke
If the core is moved out of its middle position, the impedances of the two measuring coils
change and the measuring voltage grows proportionally within the measuring range
proportionally with the displacement of the core.
4.3.2 Linear Variable Differential Transformers (LVDT)
Differential transformers consist of one primary and two secondary coils, which are coupled via
a magnetic core according to the transformer principle.
The primary coil being fed with an AC voltage induces a voltage in the secondary coils. The
output is zero due to the counter-connection of these coils, when the core is in the middle
position.
If the core is moved out of its middle position, the impedances of the two secondary coils
change and the measuring voltage grows proportionally within the measuring range
proportionally with the displacement of the core.
U
A
A
Tauch-
anker
°
°
°
°
U
SP
0 V
A
B
A
B
Oszillator
Prinzipschaltbild TF-
Verstärker
AMP
Filter
U
Mess
-s
0
+s
°
°
