Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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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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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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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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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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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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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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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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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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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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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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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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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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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
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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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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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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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Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
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The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…
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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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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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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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A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
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An important performance parameter for transmitter instruments is something often referred to as turndown or…
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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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An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
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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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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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Area refers to the size of two-dimensional surface. Volume refers to the size of a three-dimensional space. To…
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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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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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A quantitative PID tuning procedure is a step-by-step approach leading directly to a set of numerical values…
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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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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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