One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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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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It is possible to convey electrical power and communicate analog information over the same two wires using 4…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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I remember first learning about the world-wide Internet, and wondering what it actually looked like. The first…
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Light has long been used as a long-range signaling medium. While communication by light through open air is…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…
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DC electric current signals may also be used to communicate process measurement information from transmitters…
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Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…
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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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Some of the simplest types of digital communication networks found in industry are defined by the EIA…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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 very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
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A much simpler alternative to continuous vibration sensors (displacement or acceleration) and monitoring…
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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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At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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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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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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An variable-area flowmeter is one where the fluid must pass through a restriction whose area increases with…
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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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Learning how to tune PID controllers is a skill born of much practice. Regardless of how thoroughly you may…
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A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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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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Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
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Finally, we arrive at the loop diagram (sometimes called a loop sheet) for the compressor surge control system…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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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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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a…
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A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
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Learning how to tune PID controllers is a skill born of much practice. Regardless of how thoroughly you may…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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These fortifications focus on human behavior rather than system design or component selection. In some ways…
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Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…
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The following animation shows a rotating phasor in three-dimensional form. The phasor rotates in a complex…
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(Will be addressed in future versions of this book)
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In order to provide an interface between the internal (digital) world of a computer and the external (analog)…
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As we have seen, feedforward control is a way to improve the stability of a feedback control system in the…
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Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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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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Perhaps the most confusing aspect of discrete sensors is the definition of a sensor’s normal status.…
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