Balluff BTL7-P511-M J-DEXC-TA12 Series, User Manual

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3
Construction and function (continued)
Component overview
Housing cover
Electronics module (including measuring range)
Pressure housing
Conduit entry
4)
Connection terminal
6)
Retaining screws
Housing screws
5)
Float
1)
Magnet
2)
O-ring flange (not
visible)
External housing GND
Internal housing GND
Housing cover
O-ring
Adapter
3)
Cover secondary retaining
screw
Location of order code for replacement
electronics module
1) For use in liquid-level applications,
not included in scope of delivery (see section 8.1 Floats)
2) Not included in scope of delivery (see section 8.2 Magnets)
3) 1/2"-14 NPT to M20, optional (see s ection 8.3 Conduit adapter)
4) Modified 1/2"-14 NPT according to FM 3615, 3.3.3, D, 1
5) M6x45 A2 hexagon socket screws (6x, included)
(replacement screw kit: BTL7-A-FK01-E-J-DEX).
6) Wiring information (see section 4.5 Electrical connection)
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 externally generated INIT pulse interacts with the
magnetic field of the magnet to generate a torsional wave
in the waveguide which propagates at ultrasonic velocity.
The component of the torsional wave which arrives at the
end of the waveguide is absorbed in a damping zone to
prevent reflection. The component of the torsional wave
which arrives at the beginning of the waveguide is
converted by a coil into an electrical signal. The travel time
of the wave is used to calculate the position.
The position value corresponds to the travel time of the
torsional wave and is output as digital time information
between the start and stop pulses.
The evaluation may relate to the rising or falling edge. This
is done with a high level of precision and reproducibility
within the measuring range indicated as the nominal
length.
Fig. 3-2:
T
T
Start Stop
Init
Time/distance measuring principle
BTL7-P511-M _ _ _ _ -J-DEXC-TA12
Magnetostrictive Linear Position Sensor – Rod Style
Ignition protection “d”
Flameproof enclosure