Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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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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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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 reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
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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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Most of these formulae appear in molecular chemical form rather than structural form. For example, ethanol…
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To summarize some of the key points and concepts for teaching: Do not waste class time transmitting facts to…
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A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
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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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In a manually-controlled process, a human operator directly actuates some form of final control element…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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One of the most common, and most useful, pressure measuring instruments in industry is the differential…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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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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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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A fundamental limitation of proportional control has to do with its response to changes in setpoint and…
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The advent of “smart” field instruments containing microprocessors has been a great advance for…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
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Some of the simplest types of digital communication networks found in industry are defined by the EIA…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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An on/off valve is the fluid equivalent of an electrical switch: a device that either allows unimpeded flow or…
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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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Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year…
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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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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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In modern industry, the most popular form of field-level signal transmission for variable industrial…
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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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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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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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At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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