As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
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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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Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
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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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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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The next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
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Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
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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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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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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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Circuit breakers used in residential, commercial, and light industrial service are self-tripping devices: they…
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A quantitative PID tuning procedure is a step-by-step approach leading directly to a set of numerical values…
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An variable-area flowmeter is one where the fluid must pass through a restriction whose area increases with…
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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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A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…
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A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…
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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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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
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Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
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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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Light is known to interact with matter in very specific ways, which may be exploited as a means of measuring…
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Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…
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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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Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
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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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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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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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Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
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Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
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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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Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
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Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
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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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A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
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Constructing PID control systems using discrete components is a fairly simple method involving operational…
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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 the calculus concepts of differentiation and integration (with respect to time)…
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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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Instrument technicians should not have to concern themselves over the programming details internal to digital…
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Light has long been used as a long-range signaling medium. While communication by light through open air is…
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Electrical power grids primarily consist of three-phase AC circuits. This means most power lines (transmission…
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Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
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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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Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
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While the term “probability” may evoke images of imprecision, probability is in fact an exact…
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This section shows some of the many instrument symbols found in different types of technical diagrams used 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 fundamental principle of electromagnetism is that an electric current will create a magnetic field at…
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Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
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This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…
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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 is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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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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A flow switch is one detecting the flow of some fluid through a pipe. Flow switches often use…
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