Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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There are many process control applications in the industry where it is desirable to have multiple control…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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Light is known to interact with matter in very specific ways, which may be exploited as a means of measuring…
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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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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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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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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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The key to understanding how three-phase electric motors work is to have an accurate mental picture of the…
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A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
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An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
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Capacitance Any two electrical conductors separated by an insulating medium possess the characteristic called…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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A different strategy for controlling the flow of fluid is to insert a rotary element into the flow path.…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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Finally, we arrive at the loop diagram (sometimes called a loop sheet) for the compressor surge control system…
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As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
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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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