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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
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An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…
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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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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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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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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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“As to methods there may be a million and then some, but principles are few. The man who grasps…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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The efficient identification and correction of instrument calibration errors is an important function for…
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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 following animation shows how a radio-energy pulse travels down and then up the waveguide of a guided-wave…
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Finally, we arrive at the loop diagram (sometimes called a loop sheet) for the compressor surge control system…
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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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PID control can be a confusing concept to understand. Here, a brief summary of each term within PID (P. I, and…
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Perhaps the simplest form of solid or liquid level measurement is with a float: a device that rides on the…
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