The two “process variables” we rely on most heavily in the field of electrical measurement and…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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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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One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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The efficient identification and correction of instrument calibration errors is an important function for…
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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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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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An on/off valve is the fluid equivalent of an electrical switch: a device that either allows unimpeded flow or…
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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…
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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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Although analog electronic process controllers are considered a newer technology than pneumatic process…
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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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A limit switch detects the physical motion of an object by direct contact with that object. An example of a…
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As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
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Another category of control strategies involves the use of signal relays or function blocks with the ability…
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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
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A very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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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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Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…
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Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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