Limit Switches

A limit switch detects the physical motion of an object by direct contact with that object. An example of a…

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4-wire (“self-powered”) Transmitter Current Loops

DC electric current signals may also be used to communicate process measurement information from transmitters…

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Differential (87) Current Protection

One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…

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Laser Spectroscopy

A laser is a light source emitting waves of light that not only share the exact same frequency (color)…

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Thermocouple Types, Junctions, Connector and Tip Styles

RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…

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Rotating Magnetic Fields in Three-phase AC Induction Motors

The following animation shows how the “rotating” magnetic field of a three-phase AC induction…

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Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)

At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…

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Digital PID Algorithms

Instrument technicians should not have to concern themselves over the programming details internal to digital…

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Periodic Table of the Ions

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Distance (21) Protection

A form of protection against faults on long-distance power lines is called distance relaying, so named because…

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Non-dispersive Luft Detector Spectroscopy

Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…

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Conservation Laws

The Law of Mass Conservation states that matter can neither be created nor destroyed. The Law of Energy…

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Principles, not Procedures

One of the marks of a successful problem-solver is a habit of applying general principles to every new problem…

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Techniques for Analyzing Control Strategies

Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…

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The International System of Units

The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…

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Problem-solving by Simplification

A whole class of problem-solving techniques focuses on altering the given problem into a simpler form that is…

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FOUNDATION Fieldbus Design Philosophy

To understand just how different FOUNDATION Fieldbus is from other digital instrument systems, consider a…

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Classical Mechanics

Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…

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Supervisory Control

In a manually-controlled process, a human operator directly actuates some form of final control element…

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New Content

Coy, John J. et. al. (December 2012) Sampled graphic illustrations from his NASA Reference Publication…

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