Function; Number Of Magnets; Led Display - Balluff BTL7-P511...-S32 Serie Betriebsanleitung

BTL7-P511 -M _ _ _ _ -P-S32/S115/KA_ _
Magnetostrictive Linear Position Sensor – Profile Style
3
Construction and function (continued)
3.2

Function

The BTL contains the waveguide which is protected by an
aluminum housing. 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 the 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.
Init
Start
Stop
T
T
Fig. 3-2: Time/distance measuring principle
3.3

Number of magnets

Up to 16 magnets can be used. The distance (L) between
the magnets must be at least 65 mm.
L
Fig. 3-3: Distance between the magnets
8 english
L L
3.4

LED display

LED 1
LED 2
Fig. 3-4: BTL7 LED displays
LED 1
Normal function
Green
Magnet is within the limits.
Red Error
No magnet or magnet outside the limits.
LED 2
Off Normal function
Valid Init signal.
Flashing red Init error
Missing or invalid Init signal and LED 1 is off.