The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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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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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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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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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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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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The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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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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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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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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Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
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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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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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Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
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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 reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
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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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RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…
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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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Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
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The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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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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Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
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The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
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The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
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Most of these formulae appear in molecular chemical form rather than structural form. For example, ethanol…
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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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Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
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The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
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Any physical location in an industrial facility harboring the potential of explosion due to the presence of…
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First, let us review some of the properties of differentials and derivatives, referencing the expression and…
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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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The final element of PID control is the “D” term, which stands for derivative. This is a calculus…
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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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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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