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.
TEMP MEASUREMENT AND CALIBRATION
What every instrument tech should know. This article answers questions, such as: How do I measure temperature? How accurate is my measurement? What temperature range is required? And, what type of device best measures temperature? It also covers types of measurement devices: liquid in glass thermometers (LIG), thermocouples (TCs), thermistors, resistance temperature detectors (RTDs), platinum resistance thermometers (PRTs) and standard platinum resistance thermometers (SPRTs). There is also a section on calibration. The direct link is at http://tinyurl.com/49dlzs3.
Part of National Instrument's "How-To Guide for Most Common Measurements" series, this tutorial, "Temperature Measurements with Thermocouples: A How-To Guide" covers the basics of thermocouple theory and practice. It includes an overview of thermocouples and sections on "How a Thermocouple Works," "Considerations for Accurate Thermocouple Measurement," "Connecting a Thermocouple to an Instrument" and more. The direct link is at http://tinyurl.com/4oy6qu5.
"Temperature Calibration in Industrial Processes" provides an overview of the calibration process, including discussions of internal and external references, system or component calibrations and accredited calibration services. The direct link is at http://tinyurl.com/33zf5y3.
TEMPERATURE MEASUREMENT PITFALLS
This whitepaper answers the question: what do you need to know to select the best temperature measurement solution for your test and control application? It discusses some of the latest technology, such as LXI (LAN eXtensions for Instrumentation) and 24-bit Sigma-Delta A/D converters. It also covers eliminating random noise to get usable data, making data easily accessible, and the application interface. The direct link to the white paper is at http://tinyurl.com/4cmzxmz.
This is a downloadable lecture on temperature measurement covering definitions and standard calibration; thermal expansion methods; bimetallic, liquid-in-glass and pressure thermometers; the law of thermocouples, common thermocouples, reference junction considerations, measuring circuits and thermopiles; RTDs, RTD materials, three- and four-lead RTDs; junction semiconductor sensors; digital thermometers; radiation thermometry; radiation fundamentals, total radiation type and optical pyrometer; ratiometric type; and quartz crystal thermometers. The direct link is at http://tinyurl.com/4cpulr9.
INTRO TO TEMPERATURE MEASUREMENT
Temperature can be measured via a diverse array of sensors. All of them infer temperature by sensing some change in a physical characteristic. Six types with which the engineer is likely to come into contact are thermocouples, resistive temperature devices (RTDs and thermistors), infrared radiators, bimetallic devices, liquid expansion devices and change-of-state devices. This paper discusses each of these devices and its uses. The direct link is at http://tinyurl.com/y8jy48h.
THERMOCOUPLES AND RTD TABLES
This site has 35 different temperature vs. electromotive force (EMF) and temperature vs. resistance tables. All are viewable on the web or downloadable as PDFs. They cover Fahrenheit and Celcius conversions of multiple RTDs, including platinum, copper, nickel and nickel-iron RTDs, for Types B through T thermocouples and specifications for various thermocouple types. The direct link is at http://tinyurl.com/4dldurk.