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1.5 General functional description
The measuring principle is based on a run time measurement in the ultrasound area.
The ultrasound propagation time is path proportional and is evaluated in an
electronics. A ferromagnetic wire is (magnetostrictive measuring element shaft
conductor) in a reed capsule tense, this one are pressurized with a current pulse. A
radial magnetic field arises from the current pulse therefore.
The position sensor (Permanent magnet) is a non-contact and wear free
measurement magnetic system, which produces a magnetic axial field, related to the
wire. If the two magnetic fields, radially from the wire and axial from the magnet, meet
one another at the measuring point, then a torsion impulse will generated.
This torsion impulse moves as acoustic wave of the measuring body with constant
ultrasonic sound speed of the measuring point in both directions of the wire.
Over a sensing element in the sensor head the ultrasonic sound signal is recorded
and converted into electrical away-proportional output signal. The acoustic wave of the
measuring body moving in both directions are weakened in the damping zones at the
beginning and end of the measuring element.
The time difference of sending the current pulse up to the arrival of the torsion impulse
converts measuring electronics into an away-proportional output signal and makes this
available as digital or analog signal.
Measuring principle, standard measuring system:
Measuring principle, multiple redundant measuring system:
❶
Current impulse
❷
Slide wire
❸
Damping zone
❹
Position sensor (Magnet)
❺
Magnetic field, produced by a current impulse
❻
Resulting magnetic field at the position sensor
❼
Answer signal of the torsion impulse
❽
Measuring sensor Receipt coil
Printed in the Federal Republic of Germany
03/17/2021
TR-ELA-BA-DGB-0004 v16
TR-Electronic GmbH 2007, All Rights Reserved
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