An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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The key to understanding how three-phase electric motors work is to have an accurate mental picture of the…
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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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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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 addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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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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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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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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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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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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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
Textbook
There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
Textbook
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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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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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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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One of the simplest classes of temperature sensor is one where temperature effects a change in electrical…
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A great many precision instruments use the principle of balance to measure some quantity. Perhaps the simplest…
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These fortifications focus on human behavior rather than system design or component selection. In some ways…
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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…
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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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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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Visualizing the actions of P, I, and D tuning parameters using graphs is extremely useful in predicting the…
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Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year…
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The advent of “smart” field instruments containing microprocessors has been a great advance for…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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An important performance parameter for transmitter instruments is something often referred to as turndown or…
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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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By definition, a source is a device delivering energy into a system, while a load is a device extracting…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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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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A form of protection against faults on long-distance power lines is called distance relaying, so named because…
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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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At the root of successful system diagnosis is a rigorous adherence to scientific reasoning. There exists no…
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