The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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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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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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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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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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pH is the measurement of the hydrogen ion activity in a liquid solution. It is one of the most common forms of…
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One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…
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Suppose we wished to measure the consumption of propane over time for a large propane storage tank supplying a…
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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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A powerful mathematical concept useful for analyzing practically any physical system – electrical…
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A special type flowmeter suited for powdered or granular solids is the weighfeeder. One of the most common…
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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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A machine in the broad sense of the word is any device designed to translate some form of energy into useful…
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The efficient identification and correction of instrument calibration errors is an important function for…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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An important legacy technology for all kinds of continuous measurement is the self-balancing system. A…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Fluid pressure exerts force on any surface area it contacts, as described by the formula \(F = PA\). One…
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Pipe is a hollow structure designed to provide an enclosed pathway for fluids to flow, usually manufactured…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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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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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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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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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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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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Like so many other industrial data networks, FOUNDATION Fieldbus is an “unswitched” or…
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Many liquid substances undergo a process whereby their constituent molecules split into positively and…
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Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…
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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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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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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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A special type flowmeter suited for powdered or granular solids is the weighfeeder. One of the most common…
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Layer 1 of the OSI Reference Model is where we define the “physical” elements of a digital data…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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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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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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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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Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a…
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The following animation shows the calculus concepts of differentiation and integration (with respect to time)…
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