Construction; Function - Balluff BTL7-T500-M-B/Z-DEXA/B-K Serie Manual De Instrucciones

BTL7-T500-M_ _ _ _-B/Z-DEX_-K_ _/KA_ _/ZA1K
Magnetostrictive Linear Position Sensor – Rod Style
3
Construction and function (continued)
3.1

Construction

Electrical connection: The BTL is available with two
connection options: with cable out (BTL7-...-K and BTL7-
...-KA) or with separate connection housing (BTL7-...-
ZA1K), see part numbering code on page 21.
Connection is described in section 4.4 on page 14.
Housing: Housing containing the processing electronics.
Fastening: We recommend assembling these BTLs on
the mounting thread:
– BTL7-...-B: M18×1.5
– BTL7-...-Z: 3/4"-16UNF
The BTLs have an additional thread at the end of the rod
to support larger nominal lengths.
Magnet: Defines the position to be measured on the
waveguide. Magnets are available in various models and
must be ordered separately (see Accessories starting on
page 18).
Nominal length: Defines the travel/length range available.
Rods with various nominal stroke lengths from 25 mm to
7620 mm are available depending on the version.
Damping zone: Area at the end of the rod that cannot be
used for measurements, but which may be passed over.
10 english
3.2

Function

The BTL contains the waveguide which is protected by an
outer stainless steel tube (rod). A magnet is moved along
the waveguide. This magnet is connected to the system
part whose position is to be determined.
The magnet defines the position to be measured on the
waveguide. An internally generated INIT pulse interacts
with the magnetic field of the magnet to generate a
torsional wave in the waveguide which propagates at
ultrasonic speed.
The component of the torsional wave which arrives at the
end of the waveguide is absorbed in the damping zone to
prevent reflection. The wave generated at position of the
magnet returns to the head end of the BTL where a coil
converts the wave into an electrical signal. The travel time
of the wave is used to calculate the position at a resolution
of 5 µm. This is done with high precision and reproducibility
within the measuring range designated as the rated length.