Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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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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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…
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One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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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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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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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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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…
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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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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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The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
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Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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A much simpler alternative to continuous vibration sensors (displacement or acceleration) and monitoring…
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A different strategy for controlling the flow of fluid is to insert a rotary element into the flow path.…
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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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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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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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An variable-area flowmeter is one where the fluid must pass through a restriction whose area increases with…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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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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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…
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Take for instance the problem of measuring fluid flow through a pipe. To the layperson, this may seem to be a…
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The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…
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A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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Lipták, Béla G. et al., Instrument Engineers’ Handbook – Process Measurement and Analysis Volume I,…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…
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