Version 2.1
en MBI 46.31 operating instruction.docx
Issue date: 01/2022
Page 7 of 42
Term
Definition
current
principle
equivalent circuit. A movable measuring tube (made of a
conductive material) changes the impedance of the
measuring coil based on the eddy current principle.
Construction
Symmetric
sensor
The measuring coil halves of differential transformers and
inductors are built in a symmetrically (mirrored) design. The
electrical zero is at the center of the nominal stroke.
Asymmetric
sensor
The space-saving equivalent circuit of the 2
nd
coil of the long-
stroke sensors results in an asymmetric design enabling a
more favorable displacement-to-length ratio. The electrical
zero is at the start of the nominal stroke (when the measuring
tube completely covers the measuring coil).
Immersion core
(core with core
rod)
The immersion core is a two-piece, rod-shaped part
consisting of
•
a magnetic core and
•
a core rod, i.e. a purely mechanical extension made of a
non-magnetic material.
Measuring tube The measuring tube is made of aluminum. In asymmetric
displacement sensors it is moved over the measuring coil
drawin
g energy from the coil field proportional to the tube’s
position (eddy current effect).
Characteristic data
Excitation
voltage (U
sp
)
AC voltage (typically 1...5 Vpp), supplying the inductive
sensor.
Carrier
or
bridge
frequency
Excitation frequency (usually 5 or 10 kHz) to drive the
inductive displacement sensor.
