Tag: Automation
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Topological Network Structures used in Fieldbus Systems
Topology is an important property of fieldbus. It is employed in the selection and definition of the best and suitable physical layout of the fieldbus network. The physical layer of the fieldbus has to meet somewhat demanding requirements like immunity … 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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Feedforward Control
Feedforward control is based on principle of pre-emptive load counter-action i.e. if all major loads (i.e. disturbances) on a process variable are monitored, and their effects on that process variable are well-understood, a control system programmed to take the appropriate … Read more
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Benefits of Cascade Control
We know very well that closed loop control provides increased performance over open loop control. So it would be rational to expect benefits from adding inner control loop around plant items that have degrading overall performance. The Figure (a) below … Read more
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The Basics of Ladder Diagrams for Programming PLCs
The ladder diagrams are universally used as a symbolic and schematic way to represent the interconnection between the elements in a Programmable Logic Controller (PLC). The ladder network is also used as a tool for programming the operation of PLC. … Read more
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Basic Features of Distributed Control Systems (DCS)
In distributed control system, each process has its own separate controller located at the site. These local controllers are interconnected via a local area network so that all controllers on the network can be monitored or reprogrammed from a single … Read more
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Types of Sensors used in Measurement and Process Control
A sensor is an element in a measurement system that detects the magnitude of a physical variable or parameter and changes it into a signal that can be processed by the system. The active element of a sensor is often … Read more
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Basic Facts about Data Acquisition (DAQ) and Process Control
The goal of most electronic systems is to measure or control some physical quantity. The system will have to acquire data from the environment, process this data and record it. As a control system, it will also have to … Read more
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Proportional plus Derivative (PD) Control System
Proportional plus derivative (rate) control is a control mode in which a derivative section is added to the proportional controller. This derivative section responds to the rate of change of the error signal, not the amplitude as with the integral … Read more
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Why you should replace your old DCS systems with modern ones
To keep up with evolving technology manufacturers need to upgrade their legacy Distributed Control Systems (DCS). This might be a challenging task to undertake and at a cost to the company, but in the long run the benefits outweigh the … Read more