An important design parameter of a control valve is the position it will “fail” to if it loses…
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The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
Textbook
Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
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Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…
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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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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 two “process variables” we rely on most heavily in the field of electrical measurement and…
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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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In some process applications, it is important that the control valve be able to completely stop fluid flow…
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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…
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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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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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It is often useful to express the amplitude of an alternating quantity such as voltage or current in terms…
Textbook
Constructing PID control systems using discrete components is a fairly simple method involving operational…
Textbook
As we have seen, feedforward control is a way to improve the stability of a feedback control system in the…
Textbook
Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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A variety of problem-solving techniques have been presented for students over the years which are all helpful…
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The key to understanding how three-phase electric motors work is to have an accurate mental picture of the…
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Since we often use electricity to convey energy from one location to another, it is important to be able to…
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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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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
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Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
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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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A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
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Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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Up until this point, we have explored various types of instrumentation diagram, each one making reference to…
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As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
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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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A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
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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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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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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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A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
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The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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Abdelaziz, Ahmed (June 2014) Identified numerous typographical errors throughout the book, mostly repeated…
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A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
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In a manually-controlled process, a human operator directly actuates some form of final control element…
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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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A simple control system drawn in block diagram form looks like this: Information from the measuring device…
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In this section I will show screenshots from a process loop simulation program illustrating the effectiveness…
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The term “grid” refers to the conductors and equipment interconnecting power sources to power…
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In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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In contrast to quantitative tuning procedures where definite numerical values for P, I, and D controller…
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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found…
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