Light is known to interact with matter in very specific ways, which may be exploited as a means of measuring…
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As we have seen, feedforward control is a way to improve the stability of a feedback control system in the…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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 two “process variables” we rely on most heavily in the field of electrical measurement and…
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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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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
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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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Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. 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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The efficient identification and correction of instrument calibration errors is an important function for…
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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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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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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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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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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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Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
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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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The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
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One of the most common, and most useful, pressure measuring instruments in industry is the differential…
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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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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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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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When I began teaching full-time in 1998, most of what I thought I understood about good teaching was actually…
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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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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust 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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An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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A great many chemical composition measurements may be made indirectly by means of electricity, if those…
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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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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
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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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In order to provide an interface between the internal (digital) world of a computer and the external (analog)…
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