The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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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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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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Hydrogen ion activity in aqueous (water-solvent) solutions is a very important parameter for a wide variety of…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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Data-processing modules within FF systems are known as function blocks. Sometimes these blocks serve merely to…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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Sensors used to measure vibration come in three basic types: displacement, velocity, and acceleration.…
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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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One of the simplest classes of temperature sensor is one where temperature effects a change in electrical…
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Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
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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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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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To show a practical process example, let’s examine three diagrams for a compressor control system,…
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When I began teaching full-time in 1998, most of what I thought I understood about good teaching was actually…
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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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A much simpler alternative to continuous vibration sensors (displacement or acceleration) and monitoring…
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A special type flowmeter suited for powdered or granular solids is the weighfeeder. One of the most common…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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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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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…
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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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Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
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