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Introduction

From the conclusion of the performance review of advanced water level measurement technologies in irrigation applications undertaken by the Irrigation Training and Research Center (ˇ§ITRCˇ¨), under a technical services agreement with the United States Bureau of Reclamation (ˇ§USBRˇ¨), Mid-Pacific Region, ITRC gives the highest score to the Float-Operated level transducers, and recommends the use of the same whenever it is possible.

We (TWSI) have further improved the recommended cable-extension Float-Operated transducers. In applications where stilling wells are needed, such as canals, only small ones are required for the installation of our cable-extension Float-Operated transducers. And in applications where no stilling well is needed, such as tanks, our cable-extension Float-Operated transducers are less demanding than ultrasonic level transducers regarding conditions for installation.

New CET Float-Operated Level Transducers
( TW-260S series from TWSI )

Features
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  1. It includes a constant torque spring instead of a counterweight used in a conventional Float-Operated level transducer, thus eliminating the requirement that the counter-weight will be kept from the measured liquid.
  2. Without including a counter-weight, it can easily be installed, and requires only a small stilling well as necessary.
  3. It senses the movement of the measured surface by a mechanical manner in order to obviate zero and span drifts resulting from temperature fluctuation on analog sensors.
  4. It senses the movement of the measured surface by a digital manner, thus eliminating errors in ADC (analog-to-digital conversion) needed in analog sensors.
  5. Consisting of basic mechanism and measuring elements, the CET Float-Operated Level Transducers have a long stroke up to 10 meters, with a precision of 0.5 cm ˇÓ 0.1% F.S.
  6. With built-in CMOS counter module powered by Li-cell, it provides absolute readings of level measurement with less component and cost.
  7. It can be used for various types of liquid. It is not vulnerable to change in the temperature and density of the measured liquid.


BACK

 Specification
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  1. Measuring Ranges: 3m, 6m, 10m, 15m or 20m.
  2. Precision: 0.3cm ˇÓ 0.1% FS; 0.5 cm ˇÓ 0.1%FS
  3. Resolution: 0.1cm, 0.2cm, 0.5 cm
  4. Float Size: 7cm, 8.4cm, 10cm, 15cm in Diameter
  5. Power Supply: DC 5V, 0.1mA; 0.03mA Standby
  6. Output: Absolute value in TWS series protocol; converter for SDI-12, RS-485, or 4-20mA Optional
Applications
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  1. Various types of liquid such as tanks, pools and towers
  2. Fields where stilling wells can be installed such as canals, weirs, and pumping stations
  3. By the additional pulse output, flood warning stations may catch the rising water in time
Advantages

Economy, Stability, Precision and Easy Installation are taken into consideration in our cable-extension Float-Operated level transducers to the contrary of most of other level transducers.ˇ@

Benchmark

Cable-Extension Float-Operated vs. Ultrasonic
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  1. Precision, 0.15% vs. 0.25%
  2. Invulnerable to change in temperature of air above the measured surface
  3. Invulnerable to foam on the measured surface
  4. Not requiring precisely horizontal installation of the mounting plate
  5. Very low power consumption
  6. No delay to get value of level changed
Cable-Extension Float-Operated vs. Pressure
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  1. Stable and invulnerable to zero and span drifts resulting from elapsing of time
  2. Not affected by water temperature fluctuations
  3. Not affected by dirty water
  4. Low costs in maintenance
Cable-Extension Float-Operated vs. Conventional Float-Operated
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  1. Small pipe applicable to stilling well
  2. Less accessories and easy installation
  3. Free of the requirement that the counter-weight shall be kept from the measured liquid
  4. Low cost in manufacturing