DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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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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The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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 limit switch detects the physical motion of an object by direct contact with that object. An example 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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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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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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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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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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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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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In order for any PID controller to be practical, it must be able to do more than just implement the PID…
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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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A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
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A much simpler alternative to continuous vibration sensors (displacement or acceleration) and monitoring…
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The final element of PID control is the “D” term, which stands for derivative. This is a calculus…
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Like many other mathematical operations, the derivative and the integral perform inverse operations from each…
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The two “process variables” we rely on most heavily in the field of electrical measurement and…
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A variety of technologies exist to measure the quantity of stored material in a vessel. For liquid…
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Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…
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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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There are multiple motives for compromising the security of an industrial control system, some of which…
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A design-based fortification is one rooted in technical details of system architecture and functionality. Some…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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The Law of Mass Conservation states that matter can neither be created nor destroyed. The Law of Energy…
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Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
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Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
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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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Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…
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Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
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In this section I will show screenshots from a process loop simulation program illustrating the effectiveness…
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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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As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Calculus has a reputation for being difficult to learn, and with good reason. The traditional approach to…
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One of the most common, and most useful, pressure measuring instruments in industry is the differential…
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Self-balancing mechanisms consisting solely of a baffle/nozzle detector coupled to a feedback bellows, while…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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A flow switch is one that detects the flow of some fluid through a pipe. Flow switches often use…
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Certain types of nuclear radiation easily penetrates the walls of industrial vessels, but is attenuated by…
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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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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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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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Learning from reading printed text is a kind of problem-solving activity it is own right. The problem is how…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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The efficient identification and correction of instrument calibration errors is an important function for…
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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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Modern analog-to-digital converters are phenomenally accurate, dependable, repeatable, and surprisingly…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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To summarize some of the key points and concepts for teaching: Do not waste class time transmitting facts to…
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Most of these formulae appear in molecular chemical form rather than structural form. For example, ethanol…
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