Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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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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One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
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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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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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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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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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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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All masses require force to accelerate (we can also think of this in terms of the mass generating a reaction…
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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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A form of protection against faults on long-distance power lines is called distance relaying, so named because…
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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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An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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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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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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A whole class of problem-solving techniques focuses on altering the given problem into a simpler form that is…
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Lipták, Béla G. et al., Instrument Engineers’ Handbook – Process Measurement and Analysis Volume I,…
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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 next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
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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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Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
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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 following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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There are many process control applications in the industry where it is desirable to have multiple control…
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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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Converting between disparate units of measurement is the bane of many science students. The problem is worse…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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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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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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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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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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