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 [email protected], and we’ll add them to the website.
HOW LEVEL SENSORS WORK
This essay on types of process level measurement technologies focuses on various radar level measurement techniques. The site looks at some of the advances in level technologies, and highlights why pulse radar is becoming a preferred choice for process level measurement. The author has also written a book, Radar Level Measurement: A User's Guide. A direct link to the information is found at http://tinyurl.com/yh3s8pm.
MEASURE SLUDGE LEVEL
Video shows two different manual sludge level measurements. The first measurement is taken slowly, allowing water to equalize in the tube, therefore showing a reasonably accurate sludge level. The second manual measurement is taken fast, which does not allow water time to equalize in the tube, therefore a suction effect occurs that pulls the sludge with it. This gives a false reading. Therefore, the manual method is not a reliable way to measure and control sludge levels. For a direct link, go to http://tinyurl.com/yfyu6a9.
A LEVEL MEASUREMENT ORIENTATION
Part of Omega's "Transactions in Measurement & Control" series, this site covers level measurement basics. It contains sections on level sensor selection, boiling and cryogenic fluids, and sludge, foam and molten metals. A direct link is at http://tinyurl.com/yhjt7o7.
LEVEL MEASUREMENT PRINCIPLES
This article covers RF capacitance, conductance, hydrostatic tank gauging, radar, and ultrasonics, the leading sensor technologies in liquid level tank measurement and control operations. Go to http://tinyurl.com/ygmybpc for a direct link.
LEVEL BASICS—THE MOVIE
In this video, Control's editor in chief, Walt Boyes, talks about the basics of measuring level, and how to select the correct level technology for your application. Topics include wireless standards, hydrostatic level measurement, level measurement basics and more. The direct link to the video is at http://tinyurl.com/yhs6ebr.
Technical University of Darmstadt Library
Modern Sensors Handbook, edited by Pavel Pipka and Alois Tipek, is a PDF book that covers all aspects of modern sensor technology. Chapter 7 focuses on level, position and distance sensing. It covers, among other things, capacitive, ultrasonic, radar and hydrostatic level sensors. The chapter also has a list of both print and online references for further study. Go to http://tinyurl.com/yzegew9 for a direct link.
This is a brief tutorial on Pressure Level Transmitters by David Spitzer taken from the February 2009 edition of Control. Go to http://tinyurl.com/yh4euf7 for a direct link.
TANK GAUGING SYSTEM
In this eight-page PDF, the requirements of mm-precision in tank gauging under reference and application conditions are discussed. Decisive parameters of an overall concept (pulse radar, carrier frequency 6 GHz, phase evaluation, selection of antenna) are explained and their advantages are illustrated. A direct link is found at http://tinyurl.com/yz8sdz2.
LEVEL MEASUREMENT WEBSITE
This website is used as a source of information on level instruments including level sensors, level switches, level indicators and level controllers. The various techniques that are used for level monitoring and control in process plants and what measures to take for installing a sensor. Continuous, vibrating fork, rotating paddle, capacitance, and other level sensors are discussed.