An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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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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Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
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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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Pipe is a hollow structure designed to provide an enclosed pathway for fluids to flow, usually manufactured…
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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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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
Textbook
Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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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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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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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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Light has long been used as a long-range signaling medium. While communication by light through open air is…
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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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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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In our first signal characterization example, we tackle the problem of measuring fluid flow through a pipe. To…
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Process analyzers measure the concentration of specific substances for the purpose of measuring and/or…
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DC electric current signals may also be used to communicate process measurement information from transmitters…
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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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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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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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Flow, by definition, is the passage of material from one location to another over time. So far this chapter…
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An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
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A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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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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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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Perhaps the simplest form of solid or liquid level measurement is with a float: a device that rides on the…
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Another category of control strategies involves the use of signal relays or function blocks with the ability…
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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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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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