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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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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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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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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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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A limit switch detects the physical motion of an object by direct contact with that object. An example of 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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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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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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 simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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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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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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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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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…
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Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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Learning is not merely a process of information transfer. It is first and foremost a transformation of…
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When I began teaching full-time in 1998, most of what I thought I understood about good teaching was actually…
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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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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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Up until this point, we have explored various types of instrumentation diagram, each one making reference to…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
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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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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year…
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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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A flow switch is one detecting the flow of some fluid through a pipe. Flow switches often use…
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Any conductor possesses a characteristic called inductance: the ability to store energy in the form 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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