Light has long been used as a long-range signaling medium. While communication by light through open air is…
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It is possible to convey electrical power and communicate analog information over the same two wires using 4…
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I remember first learning about the world-wide Internet, and wondering what it actually looked like. The first…
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DC electric current signals may also be used to communicate process measurement information from transmitters…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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Layer 1 of the OSI Reference Model is where we define the “physical” elements of a digital data…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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Some of the simplest types of digital communication networks found in industry are defined by the EIA…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…
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pH is the measurement of the hydrogen ion activity in a liquid solution. It is one of the most common forms of…
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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…
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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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In order for any PID controller to be practical, it must be able to do more than just implement the PID…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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An important legacy technology for all kinds of continuous measurement is the self-balancing system. A…
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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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A special type flowmeter suited for powdered or granular solids is the weighfeeder. One of the most common…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…
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Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
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In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances…
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Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…
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In modern industry, the most popular form of field-level signal transmission for variable industrial…
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A variety of technologies exist to measure the quantity of stored material in a vessel. For liquid…
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The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
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Suppose we wished to measure the rate of propane gas flow through a hose to a torch: Flowmeters appropriate…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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The vast majority of modern process transmitters (both analog and digital) come equipped with a feature known…
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