Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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An important design parameter of a control valve is the position it will “fail” to if it loses…
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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 flow switch is one that detects the flow of some fluid through a pipe. Flow switches often use…
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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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pH is the measurement of the hydrogen ion activity in a liquid solution. It is one of the most common forms of…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…
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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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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous 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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As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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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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Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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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Capacitance Any two electrical conductors separated by an insulating medium possess the characteristic called…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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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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A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
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A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large…
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A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
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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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Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
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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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Another category of control strategies involves the use of signal relays or function blocks with the ability…
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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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The vast majority of modern process transmitters (both analog and digital) come equipped with a feature known…
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In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances…
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(Will be addressed in future versions of this book)
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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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The following animation shows the calculus concepts of differentiation and integration (with respect to time)…
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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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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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One of the simplest classes of temperature sensor is one where temperature effects a change in electrical…
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These fortifications focus on human behavior rather than system design or component selection. In some ways…
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A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
Textbook
Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
Textbook
In reliability engineering, it is important to be able to quantity the reliability (or conversely, the…
Textbook
Another category of control strategies involves the use of signal relays or function blocks with the ability…
Textbook
In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
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Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
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Many liquid substances undergo a process whereby their constituent molecules split into positively and…
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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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DC electric current signals may also be used to communicate process measurement information from transmitters…
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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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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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Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
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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 Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
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Perhaps the most confusing aspect of discrete sensors is the definition of a sensor’s normal status.…
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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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A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
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