A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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In some process applications, it is important that the control valve be able to completely stop fluid flow…
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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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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Up until this point, we have explored various types of instrumentation diagram, each one making reference to…
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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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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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Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
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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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At the root of successful system diagnosis is a rigorous adherence to scientific reasoning. There exists no…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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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 November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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Tube, like pipe, is a hollow structure designed to provide an enclosed pathway for fluids to flow. In the case…
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Area refers to the size of two-dimensional surface. Volume refers to the size of a three-dimensional space. To…
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As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
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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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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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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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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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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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One of the great benefits of digital technology is the ability to communicate vast amounts of information over…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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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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Light is known to interact with matter in very specific ways, which may be exploited as a means of measuring…
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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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Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…
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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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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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Coy, John J. et. al. (December 2012) Sampled graphic illustrations from his NASA Reference Publication…
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Process analyzers measure the concentration of specific substances for the purpose of measuring and/or…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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Learning from reading printed text is a kind of problem-solving activity it is own right. The problem is how…
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An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
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Up until this point, we have explored various types of instrumentation diagram, each one making reference to…
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The fundamental principle of electromagnetism is that an electric current will create a magnetic field at…
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These fortifications focus on human behavior rather than system design or component selection. In some ways…
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Suppose we wished to measure the consumption of propane over time for a large propane storage tank supplying a…
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The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…
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Feedback obtained from industrial users of FF reveal a common pattern: Fieldbus is a powerful and reliable…
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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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This section does not describe a particular type of flowmeter, but rather a design that may be implemented for…
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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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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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All masses require force to accelerate (we can also think of this in terms of the mass generating a reaction…
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