Every month, Control's editors take a specific product area, collect all the latest, significant tools we can find, and present them here to make your job easier. If you know of any tools and resources we didn't include, send them to firstname.lastname@example.org, and we'll add them to the website.
LEVEL MEASUREMENT BASICS
Transactions in Measurement & Control, Vol. 4, Flow and Level Measurement is a 113-page, free, downloadable PDF covering the basics of level measurement. Topics include level sensor selection, pressure/density, FG/capacitance and radiation-based instrumentation, and specialty level switches. The direct link is at http://tinyurl.com/42oampo.
GUIDED-WAVE RADAR VS. DIFFERENTIAL PRESSURE
This free, downloadable PDF explores the differences between level measurement by means of guided-wave radar systems and differential pressure transmitters. Although DP transmitters presently remain the dominant instrument for level measurement, their worldwide market share is expected to steadily erode in the presence of growing demand for the newer level measurement technologies. Leading the assault is guided-wave radar (GWR), which is among the most versatile of technologies now being used for liquid level measurement. The white paper compares and contrasts the two technologies, and explains the advantages of the guided-wave approach for many applications. The direct link is at http://tinyurl.com/3myh39o.
ALL ABOUT LEVEL MEASUREMENT
This three-part series covers liquid level measurement. The first part focuses on hydrostatic level measurement. The second part focuses on continuous liquid level measurement using newer technologies. This third part focuses on electronic floats, ultrasonic gap switches, thermal dispersion switches, conductivity probes and vibrating forks. All parts are free, but require registration. Direct links are as follows: Part 1--http://tinyurl.com/3sl2wg9; Part 2--http://tinyurl.com/3zo75tp; Part 3--http://tinyurl.com/3ha4ezd.
LEVEL MEASUREMENT TECHNIQUES
This link takes you to a five-part series on various techniques for measuring level. Part 1 discusses basic principles behind the techniques for measuring liquids, solids and slurries: pressure, level-sight, radiation, sonic principles and electrical properties, as well as a variety of techniques and equipment and advice for choosing the most appropriate method for your application. Part 2 covers pressure instruments. Part 3 is on radar level measurement basics, and Part 4 discusses using ultrasonics to measure level. Part 5 discusses capacitance level measurement techniques. The direct link is at http://www.indumart.com/literature.html.
LEVEL-SENSING WHITE PAPERS
Two free, downloadable white papers from Turck, "Capacitive Sensors Help Solve Difficult Measuring Applications" and "Unraveling the Complexities of Level Sensing," cover some of the challenges of level measurement. Both are available at http://www.turck-usa.com/Support/White_Papers_~_Tutorials/. They are part of a much larger white paper library covering sensing applications.
LEVEL MEDIA OF ALL SORTS
Blue Level Technologies Media pages on the company website contain a variety of information on level measuring technologies and problems. Podcasts, presentations, articles, white papers, videos and RSS feeds are all available. Most are free and downloadable. The direct link is at http://www.blueleveltechnologies.com/media.php.
blue level technologies
HOW MAGNETOSTRICTION WORKS
In a linear-position or liquid-level sensor, a sonic strain pulse is induced in a specially designed magnetostrictive waveguide by the momentary interaction of two magnetic fields. This link provides a Flash presentation showing how such sensors work. Go to http://tinyurl.com/abyoty and click on the illustration to activate the Flash file.