The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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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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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
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Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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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 efficient identification and correction of instrument calibration errors is an important function for…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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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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Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
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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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Data-processing modules within FF systems are known as function blocks. Sometimes these blocks serve merely to…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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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 powerful mathematical concept useful for analyzing practically any physical system – electrical…
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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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Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
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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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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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Learning how to tune PID controllers is a skill born of much practice. Regardless of how thoroughly you may…
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The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…
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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 great many precision instruments use the principle of balance to measure some quantity. Perhaps the simplest…
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Learning is not merely a process of information transfer. It is first and foremost a transformation of…
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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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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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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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Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…
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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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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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The final element of PID control is the “D” term, which stands for derivative. This is a calculus…
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Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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Shown here is a partial listing of principles applied in the subject matter of this chapter, given for the…
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(Will be addressed in future versions of this book)
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A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…
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Perhaps the most valuable skill an instrument technician can possess is the ability to efficiently diagnose…
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DC electric current signals may also be used to communicate process measurement information from transmitters…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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Learning how to tune PID controllers is a skill born of much practice. Regardless of how thoroughly you may…
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Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…
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One of the marks of a successful problem-solver is a habit of applying general principles to every new problem…
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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 limit switch detects the physical motion of an object by direct contact with that object. An example of a…
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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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