The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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In order for any PID controller to be practical, it must be able to do more than just implement the PID…
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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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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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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
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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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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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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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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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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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Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
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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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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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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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There are multiple motives for compromising the security of an industrial control system, some of which…
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In reliability engineering, it is important to be able to quantity the reliability (or conversely, the…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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A unique form of differential pressure-based flow measurement deserves its own section in this flow…
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A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
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Take for instance the problem of measuring fluid flow through a pipe. To the layperson, this may seem to be a…
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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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A whole class of problem-solving techniques focuses on altering the given problem into a simpler form that is…
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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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Stoichiometry is the accounting of atoms before and after a chemical reaction. It is an expression of the Law…
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A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
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The following animation shows a rotating phasor in three-dimensional form. The phasor rotates in a complex…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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Area refers to the size of two-dimensional surface. Volume refers to the size of a three-dimensional space. To…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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The majority of flowmeter technologies operate on the principle of interpreting fluid flow based on the…
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A laser is a light source emitting waves of light that not only share the exact same frequency (color)…
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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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I remember first learning about the world-wide Internet, and wondering what it actually looked like. The first…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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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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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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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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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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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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One of the marks of a successful problem-solver is a habit of applying general principles to every new problem…
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A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
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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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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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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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A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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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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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…
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