Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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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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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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The Law of Mass Conservation states that matter can neither be created nor destroyed. The Law of Energy…
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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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At the root of successful system diagnosis is a rigorous adherence to scientific reasoning. There exists no…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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Earlier in this chapter you were shown a model of a nitrogen atom with a dense nucleus (comprised of protons…
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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
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Recall that an exothermic chemical reaction is one that releases a net sum of energy, as opposed to an…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
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Feedback obtained from industrial users of FF reveal a common pattern: Fieldbus is a powerful and reliable…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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Sensors used to measure vibration come in three basic types: displacement, velocity, and acceleration.…
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A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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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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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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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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A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
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A quantitative PID tuning procedure is a step-by-step approach leading directly to a set of numerical values…
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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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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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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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The following animation shows how a radio-energy pulse travels down and then up the waveguide of a guided-wave…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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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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Once while working as an instrument technician in an aluminum foundry, a mechanic asked me what it was that I…
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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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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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Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
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Visualizing the actions of P, I, and D tuning parameters using graphs is extremely useful in predicting the…
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Fluid pressure exerts force on any surface area it contacts, as described by the formula \(F = PA\). One…
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