A proximity switch is one detecting the proximity (closeness) of some object. By definition, these 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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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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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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The majority of flowmeter technologies operate on the principle of interpreting fluid flow based on the…
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The advent of “smart” field instruments containing microprocessors has been a great advance for…
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The following animation shows the calculus concepts of differentiation and integration (with respect to time)…
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This section does not describe a particular type of flowmeter, but rather a design that may be implemented for…
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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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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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To review, voltage is the measure of potential energy available to electric charges. Current is the uniform…
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PID control can be a confusing concept to understand. Here, a brief summary of each term within PID (P. I, and…
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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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At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
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Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…
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Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
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DC electric current signals may also be used to communicate process measurement information from transmitters…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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Since we often use electricity to convey energy from one location to another, it is important to be able to…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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(Will be addressed in future versions of this book)
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Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…
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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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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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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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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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Light has long been used as a long-range signaling medium. While communication by light through open air is…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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Shown here is a partial listing of principles applied in the subject matter of this chapter, given for the…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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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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What is Calibration? To calibrate an instrument means to check and adjust (if necessary) its response so the…
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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
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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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