Tag: process control
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Instrumentation Sensors and Transducers – Multiple Choice Questions & Answers (MCQ4)
The Answers have been provided at the end of the Questions: Q1. Which of the following sensors is used to measure displacement? A. Thermistor B. LVDT C. Dall tube D. None of the above Q2. Which of the below … Read more
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How Signal Processing Circuits are protected from high currents & voltages
Protection against high currents and voltages is a very important requirement for signal processing circuits. A high current can be protected against by the incorporation in the input line of a series resistor to limit the amount of current flowing … Read more
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Basic Features of Foundation Fieldbus (FF)
Foundation fieldbus (FF) and Profibus are the two most universal serial data bus formats that are used for interfacing between the central processor and smart devices in the process control system. The Foundation Fieldbus is mainly used in U.S. while … Read more
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Features of Stepper Motors & How they are applied in Industrial Control
A stepper motor is a permanent magnet or variable reluctance DC motor that has the following characteristics: It is able to rotate in both directionsIt can move in precise angular incrementsIt can sustain holding torque at zero speed… Read more
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How Servo Motors are used in Process Control
Servo motors are continuous motion mechanisms that use feedback signals to provide position and velocity control in a closed loop system. Servo motors can rotate to a given position be stopped and reversed. The angular position and speed can … Read more
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What is a Smart Sensor?
A smart sensor is the integration of a sensor with an analogue to digital converter (ADC), a processor and digital to analogue converter (ADC) for actuator control. A typical application of a smart sensor set up is a temperature control … Read more
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Basic Features of Modern PID Controllers
Most modern PID controllers have the following features: Manual versus automatic modeOutput trackingSetpoint trackingAlarm capabilitiesProcess variable (PV) characterization and dampingSetpoint limitsOutput limitsPID tuning security Manual and Automatic Modes When the controller manually calculates … Read more
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Direct Digital Control (DDC)
In direct digital control (DDC) a single computer is able to carry out PID control for multiple loops at the same time make that loop data accessible between loops for purposes of cascade control, feedforward control, ratio control… Read more
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P&IDs and Loop Diagrams
Process and Instrument Diagrams (P&IDs), also called Piping and Instrumentation Diagrams and Loop diagrams are construction and documentation drawings that show the flow of the process and illustrate the instrumentation control and measurement instructions, wiring and connections to the process.… Read more
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Ratio Control
In some processes, it is a common requirement for two flows to be kept in precise ratio to each other for example, a gas or oil and air in combustion control, and reagents being fed to a chemical reactor hence … Read more