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TIENet™ 360 LaserFlow™ Velocity Sensor
Section 2 Preparation and Installation
2.2 Sensor Installation
Considerations
2.2.1 Ultrasonic Beam Angle
Figure 2-1 Ultrasonic level sensor beam angle
2.2.2 High Water Levels
2.2.3 Submersion and
Fouling
2.2.4 Humidity
2-2
Measurement accuracy can be affected by a number of site
factors that should be taken into consideration when selecting
the location for the sensor.
These factors may affect the laser velocity or the ultrasonic level,
or both.
If the laser velocimeter or ultrasonic transducer cannot obtain a
valid reading at any measurement point, an asterisk (*) will
appear next to the displayed reading, indicating there is an error.
The ultrasonic level transducer has a 10° beam angle (5° from
center line), forming a cone in which the apex is the transducer.
The transducer can only detect surfaces within this cone.
The ultrasonic beam narrows as elevation decreases, which can
increase difficulty in detecting the return echo. Narrow channels
can result in false echoes and incorrect level readings from the
walls and sides of the channel.
The beam widens as elevation increases. If the beam is too wide,
the sensor may pick up signals from unwanted surfaces, such as
the walls of the channel.
In most open channel installations where the level may exceed
one-half of the full pipe, mount the sensor as near as possible to
the midpoint between the entrance and exit to measure over the
least turbulent flow.
Fouling by grease or solids can cause the LaserFlow sensor to
malfunction. The LaserFlow is sealed, so unless it is exposed to
corrosive substances, submersion of 2 meters, up to 72 hours will
not harm it. Upon retrieval, ensure that the surfaces of the laser
window and ultrasonic sensor are clean.
Cleaning instructions are provided in Section 5.
Conditions of extremely high or low humidity can cause ultra-
sonic level detection to occur either earlier or later than normal
conditions. A drop in water level, normally compensated for by
the sensor's interval-based amplifier, may produce errors in echo
detection.
10°
5°
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