Datasheet

Ultrasonic sensors made by
Pepperl + Fuchs operate with Piezo-
ceramics as sound emitter and
receiver. A patented decoupling layer
in special material is used to de-
couple the ultrasonics to the air – an
acoustically thin medium.
This ultrasonic transducer is embed-
ded, watertight, into the sensor
housing, in polyurethane foam. The
transducer transmits a packet of
sonic pulses and converts the echo
pulse into voltage. The integrated
controller computes the distance
from the echo time and the velocity
of sound. The transmitted pulse
duration t and the decay time of
the sonic transducer result in an
unusable area in which the ultrasonic
sensor cannot detect an object.
unusable
area
sensing range s
d
target
opening angle
of the sound cone
maximum
switching distance
actual
switching distance
or switching window
A1
A2
minimum
switching distance
s
The ultrasonic frequency lies between
65 kHz and 400 kHz, depending on
the sensor type; the pulse repetition
frequency is between 14 Hz and 140
Hz.
The active range of the ultrasonic
sensor is referred to as the detection
range s
d
. This range is bounded by
the lowest and highest sensing dis-
tances, whose values depend on the
characteristics of the transducer. The
highest sensing distance is given in
the type code.
The sound cone detects objects which
move along a line through the axis of
the sensor or move laterally into the
cone.
Ultrasonic sensors are available with
switching outputs and/or analogue out-
puts and/or Rs 232 interface; various
output functions are available.
Ultrasonic Sensors
Principles and Technology
2