An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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Although analog electronic process controllers are considered a newer technology than pneumatic process…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…
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Hydrogen ion activity in aqueous (water-solvent) solutions is a very important parameter for a wide variety of…
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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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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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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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A positive displacement flowmeter is a cyclic mechanism built to pass a fixed volume of fluid through with…
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This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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Shown here is a partial listing of principles applied in the subject matter of this chapter, given for the…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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Data-processing modules within FF systems are known as function blocks. Sometimes these blocks serve merely to…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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A machine in the broad sense of the word is any device designed to translate some form of energy into useful…
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