Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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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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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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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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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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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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When control valves operate between fully open and fully shut, they serve much the same purpose in process…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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The efficient identification and correction of instrument calibration errors is an important function for…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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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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There are many process control applications in the industry where it is desirable to have multiple control…
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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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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
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Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
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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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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 advent of “smart” field instruments containing microprocessors has been a great advance for…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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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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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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A very common method for directly controlling low flow rates of fluids is to use a device known as a metering…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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