Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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Volumes could be written about poor diagnostic technique. The following mistakes are not intended to comprise…
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A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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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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A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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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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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…
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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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PID control can be a confusing concept to understand. Here, a brief summary of each term within PID (P. I, and…
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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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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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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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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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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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A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
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A limit switch detects the physical motion of an object by direct contact with that object. An example of a…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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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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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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A flow switch is one detecting the flow of some fluid through a pipe. Flow switches often use…
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Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
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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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Impedance in a series circuit is the orthogonal sum of resistance and reactance: \[Z = \sqrt{R^2 + (X_L -…
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Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year…
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Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
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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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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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(Will be addressed in future versions of this book)
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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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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When control valves operate between fully open and fully shut, they serve much the same purpose in process…
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