| Level control for
irrigation canals, rivers,
and streams can easliy
be done. |
The range and the
accuracy is the competative advantage.
Rivers, snowfields, streams and irrigation canals
can be monitored through the use of ultrasonic level
sensors, hydrostatic pressure transducers or cable
displacement transducers attached to a float. Flow
rate is a function of the difference in level over a
weir or through a flume. The flow characteristics are
consistent with such a constriction, and a change in
level is proportional to a change in flow. This
technique for monitoring flow is known as "open
channel flow." It is a dependable way to relate
surface level changes to changes in flow rate. The
level can be found by using a ultrasonic, a
submersible pressure transducer, or a cable
displacement transducer with a float.
Ultrasonic technology offers several advantages
over contacting level measurement devices in
stream staging applications. The sensor is not in
contact with the water. So in areas prone to flooding
or high degree of scouring from sand and gravel in
the streambed, there is no threat of the sensor being
washed down stream. Ultrasonic sensors are not
prone to fouling from build up of sediment, as
pressure transducers are. Ultrasonic sensors can be
mounted without a stilling well saving installation
expense. However, the sensors will function reliably
in existing stilling wells. Automation Products Group, Inc. ultrasonic sensors have
a wide operating temperature range, making them quite suitable for
outdoor operation.
It is possible to modulate or control flow from the
changes in level by monitoring gate position using a
cable displacement transducer. Telemetry and data
logging may be added to the controller to provide
remote monitoring of flow rates. |
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| Submersible Liquid Level Transmitter |
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Simple to install liquid level measurement |
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High precision, solid state signal: 4-20 mA
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Irrigation Level and Control
|
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Maximum range from 9 in. to 25 ft. (0.22 to 8 m) |
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Works on solids or liquids |
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Analog and trip point outputs |
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AutoSense software available on most sensors |
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Internal temperature compensation available |
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Many models are serial interface programmable
with free software for Windows or Palm
Operating System
|
| Displacement
Transducer/Transmitter |
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Standard accuracy ±0.1% F.S.*
* 0-2 in. and 0-5 in. are ±0.25% F.S.
Accuracy 0-10 in. and 0-15 in. and 0-25 in. ±0.15% |
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Voltage or 4-20 mA current output |
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Extra long-life replaceable cable |
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Precision hybrid potentiometer |
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Anodized and powder coated aluminum
construction
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