Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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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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When control valves operate between fully open and fully shut, they serve much the same purpose in process…
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(Will be addressed in future versions of this book)
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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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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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The vast majority of modern process transmitters (both analog and digital) come equipped with a feature known…
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Developed by the Modicon company (the original manufacturer of the Programmable Logic Controller, or PLC) in…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
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The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
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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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The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
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Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…
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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 fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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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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Process analyzers measure the concentration of specific substances for the purpose of measuring and/or…
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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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The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
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One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…
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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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The next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
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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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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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(Will be addressed in future versions of this book)
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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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Sensors used to measure vibration come in three basic types: displacement, velocity, and acceleration.…
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Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing 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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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found…
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A quantitative PID tuning procedure is a step-by-step approach leading directly to a set of numerical values…
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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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Atom: the smallest unit of matter that may be isolated by chemical means. Particle: a part of an atom,…
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To understand just how different FOUNDATION Fieldbus is from other digital instrument systems, consider a…
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