APG DCU-1100 user manual - Manual (Page 5)

Rev. A2, 11/06 DCU-1104 and DCU-1108
5
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• Understanding Ultrasonics
Ultrasonic sensors measure distance
using a transducer to send out ultrasonic
bursts. Each burst contains a series of 1-
20 pulsed sound waves that emit in the
shape of a cone, reflect off the target, and
are received by the sensor. The time
required for the sound burst to travel to
and from the target is converted into a
distance measurement by the sensor.
Ultrasonic sensing is affected by
several factors including the target
surface, distance, size, and angle. The
following considerations will help ensure
the best possible target conditions.
Surface
The ideal target surface is hard and smooth and perpendicular to the face of
the transducer. This surface will reflect a greater amount of signal than a soft,
sound wave absorbent surface. A target with poor sound wave reflection
characteristics will reduce the operating distance of the sensor and decrease its
accuracy.
detection
area
beam spread
low sensitivity
and
pulses
high sensitivity
and
pulses