Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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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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Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
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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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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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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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A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
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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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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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Self-balancing mechanisms consisting solely of a baffle/nozzle detector coupled to a feedback bellows, while…
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An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
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A whole class of problem-solving techniques focuses on altering the given problem into a simpler form that is…
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The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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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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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…
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Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…
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Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
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One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…
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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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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…
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For better or worse, there are no fewer than three different forms of PID equations implemented in modern PID…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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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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A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
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A powerful mathematical concept useful for analyzing practically any physical system – electrical…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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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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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
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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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Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…
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Thermodynamics is the study of heat, temperature, and their related effects in physical systems. As a subject,…
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Although analog electronic process controllers are considered a newer technology than pneumatic process…
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Visualizing the actions of P, I, and D tuning parameters using graphs is extremely useful in predicting the…
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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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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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Classical mechanics (often called Newtonian mechanics in honor of Isaac Newton) deal with forces and motions…
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