The majority of flowmeter technologies operate on the principle of interpreting fluid flow based on the…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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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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As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
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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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An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
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A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
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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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The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
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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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The transformer is one of the most important components in all of AC circuitry. Principally used to…
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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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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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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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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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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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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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Perhaps the most valuable skill an instrument technician can possess is the ability to efficiently diagnose…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
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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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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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In contrast to quantitative tuning procedures where definite numerical values for P, I, and D controller…
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To review, voltage is the measure of potential energy available to electric charges. Current is the uniform…
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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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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
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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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What is Calibration? To calibrate an instrument means to check and adjust (if necessary) its response so the…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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Coy, John J. et. al. (December 2012) Sampled graphic illustrations from his NASA Reference Publication…
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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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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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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 form of protection against faults on long-distance power lines is called distance relaying, so named because…
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Suppose we wished to measure the rate of propane gas flow through a hose to a torch: Flowmeters appropriate…
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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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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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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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