Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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A flow switch is one that detects the flow of some fluid through a pipe. Flow switches often use…
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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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A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
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Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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A pressure switch is one that detects the presence of fluid pressure. Pressure switches often use diaphragms…
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A great many chemical composition measurements may be made indirectly by means of electricity, if those…
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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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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 form of protection against faults on long-distance power lines is called distance relaying, so named because…
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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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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Any physical location in an industrial facility harboring the potential of explosion due to the presence of…
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The advent of “smart” field instruments containing microprocessors has been a great advance for…
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Although analog electronic process controllers are considered a newer technology than pneumatic process…
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A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…
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This section does not describe a particular type of flowmeter, but rather a design that may be implemented for…
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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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An important legacy technology for all kinds of continuous measurement is the self-balancing system. A…
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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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The vast majority of modern process transmitters (both analog and digital) come equipped with a feature known…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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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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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
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Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…
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Most people reading this book have likely had the experience of adjusting water temperature using two hand…
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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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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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(Will be addressed in future versions of this book)
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Sensors used to measure vibration come in three basic types: displacement, velocity, and acceleration.…
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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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All masses require force to accelerate (we can also think of this in terms of the mass generating a reaction…
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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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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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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
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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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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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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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The next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
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Thermodynamics is the study of heat, temperature, and their related effects in physical systems. As a subject,…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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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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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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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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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