At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
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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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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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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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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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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A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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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 engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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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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Learn about Modbus function codes, the structure of Modbus message packets, and the various types of channels used to transmit Modbus telegrams between controllers.
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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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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A much simpler alternative to continuous vibration sensors (displacement or acceleration) and monitoring…
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Calculus has a reputation for being difficult to learn, and with good reason. The traditional approach to…
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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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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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As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
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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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Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…
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A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…
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In this section I will show screenshots from a process loop simulation program illustrating the effectiveness…
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Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…
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A variety of problem-solving techniques have been presented for students over the years which are all helpful…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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Converting between disparate units of measurement is the bane of many science students. The problem is worse…
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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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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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Most of these formulae appear in molecular chemical form rather than structural form. For example, ethanol…
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A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
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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 hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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As a general rule, high achievement only takes place in an atmosphere of high expectations. Sometimes these…
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Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…
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The following animation shows how a radio-energy pulse travels down and then up the waveguide of a guided-wave…
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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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This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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One of the most common, and most useful, pressure measuring instruments in industry is the differential…
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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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A flow switch is one that detects the flow of some fluid through a pipe. Flow switches often use…
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An important performance parameter for transmitter instruments is something often referred to as turndown or…
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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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Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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