The three “elementary” particles of matter comprising all atoms are electrons, protons, and…
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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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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a…
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As we have seen, feedforward control is a way to improve the stability of a feedback control system in the…
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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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To summarize some of the key points and concepts for teaching: Do not waste class time transmitting facts to…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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The concepts of calibration (trimming) and ranging are often difficult for new students of instrumentation to…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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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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The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…
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In some process applications, it is important that the control valve be able to completely stop fluid flow…
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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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Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…
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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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The next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
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A positive displacement flowmeter is a cyclic mechanism built to pass a fixed volume of fluid through with…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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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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Capacitance Any two electrical conductors separated by an insulating medium possess the characteristic called…
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Measuring the flow rate of liquid through an open channel is not unlike measuring the flow rate of a liquid…
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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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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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An on/off valve is the fluid equivalent of an electrical switch: a device that either allows unimpeded flow or…
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Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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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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First, let us review some of the properties of differentials and derivatives, referencing the expression and…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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A very common method for directly controlling low flow rates of fluids is to use a device known as a metering…
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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 unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
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