An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
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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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As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
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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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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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When control valves operate between fully open and fully shut, they serve much the same purpose in process…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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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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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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Perhaps the most valuable skill an instrument technician can possess is the ability to efficiently diagnose…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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(Will be addressed in future versions of this book)
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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
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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 electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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A control strategy similar to ratio control is relation control. This is similar to ratio control in that a…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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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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As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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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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In reliability engineering, it is important to be able to quantity the reliability (or conversely, the…
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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large…
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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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Many liquid substances undergo a process whereby their constituent molecules split into positively and…
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The following animation shows the calculus concepts of differentiation and integration (with respect to time)…
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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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