Tag: process control
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What is Optimal Control?
Optimal control is whereby the requirements are formulated as either the minimization of a cost index or the maximization of a performance index of an operational control system. Optimal control is utilized in a number of disciplines such as aircraft … Read more
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Pneumatic Signal Transmission System
Signal transmission in process instrumentation and control systems is largely done via electrical transmission but there are a few areas where pneumatic transmission of signals is vital especially where electrical signals or sparks can ignite combustible materials for example in … Read more
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How Redundancy is Achieved in Process Plants
In similar way to electronic systems, redundancy is extensively employed technique for enhancing the reliability of many industrial plants and processes. Because many process plants units such as pumps, valves and compressors involve moving parts, they are prone to wear … Read more
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Phase Locked Loop High Precision Motor Speed Control System
AC generators can be utilized in high precision control systems. The AC generator rotor is rotated by the rotating shaft (i.e. the shaft from the motor being controlled). The output AC frequency is proportional to shaft speed. Zero crossings per … Read more
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Principle of Operation of Magnetostrictive Position Sensors
Magnetostrictive sensors detect the location of a magnetic ring that slides along a conductive metal tube; in other words this sensor operation utilizes the effect of a magnetic field on magnetostrictive wire to function. The figure below illustrates a Magnetostrictive … Read more
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How to Connect Discrete Sensors to PLC Inputs
Discrete Sensor Outputs Basically sensor outputs can be categorized into two types: discrete also referred to discrete or logic and proportional also called analog. Discrete sensors supply a single logical output (1 or 0) e.g. a flow switch used … Read more
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NAMUR NE 107 Standard for Modern Instrumentation Diagnostics
NAMUR NE 107 is a standard adhered to by manufacturers during the design and fabrication of instruments. NAMUR NE 107 provides status signals that communicate clear messages and remedies. These status signals or diagnostic codes are categorized into four standard … Read more
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Steam Conditioning Valves – Features, Advantages & Applications
The Work of Steam Conditioning Valves & Why they are used in Industrial Processes Typically in an industrial set up, it may be necessary downstream of the main process application of superheated steam to reduce its pressure and temperatures to … Read more
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What is the Function of a Steam Desuperheater?
Whereas superheated steam offers an excellent source of energy for mechanical power generation, in most cases, steam at greatly reduced temperatures, near saturation, proves a more desirable commodity especially for most heat-transfer applications. Precise temperature control is required to enhance … Read more
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Control Valve Selection Guide
Valves are manual or automatic fluid controlling elements in a piping system; in other words, valves isolate, switch, and control fluid flow in piping systems. They are constructed to withstand specific range of temperature, pressure, corrosion, and mechanical stress. Valves … Read more