APG LPU-2428 user manual - Manual (Page 6)

LPU-2428 Rev. A3, 11/08
6
Automation Products Group, Inc.
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Distance
The shorter the distance from the sensor to an object, the stronger the
returning echo will be. Therefore, as the distance increases, the object requires
better reflective characteristics to return a sufficient echo.
Size
A large object will have a greater surface area to reflect the signal than a
small one, therefore, a large target will be detected at a greater distance than a
small target. The surface area recognized as the target is generally the portion
closest to the sensor.
Angle
The inclination of the object's surface facing the ultrasonic sensor affects the
reflectivity of the object. The portion perpendicular to the sensor returns the
echo. If the entire surface is at a great enough angle, the signal will be reflected
away from the sensor and no echo will be detected. Generally a target at an
angle greater than 5° off perpendicular will not be detected.
Environmental Conditions
Temperature, humidity, gases, dust, and pressure may also affect the sensor’s
performance. APG ultrasonic sensors automatically compensate for many of
these conditions. However, these conditions can degrade the sensor’s
performance enough it may be necessary to use a longer-range sensor than
normal conditions would require.
1 ft.
2 ft.
3 ft.
4 ft.
5 ft.
6 ft.
7 ft.
8 ft.
9 ft.
10 ft.
Sensor
Typical Beam Pattern of a Ceramic Transducer
at high sensitivity and power settings.
0.317'
0.634' 0.950' 1.267' 1.584' 1.901' 2.217' 2.534' 2.851' 3.168'