Tag: process control
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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 interact with the environment. The flow of information in a typical data acquisition (DAQ) can be…
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Proportional-Integral-Derivative (PID) Control Systems
Proportional-Integral-Derivative For processes that are able to operate with continuous cycling, the relatively inexpensive two position controller is sufficient. For processes that cannot tolerate continuous cycling, a proportional controller is used. For processes that tolerate neither cycling nor offset error, a proportional plus integral/reset controller can be used. For processes that require improved stability and…
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Proportional Plus Integral (PI) Control System
This type of control is combination of two control modes, proportional and integral (reset). The Combining of the two modes results in gaining the advantages and compensating for the disadvantages of the two individual control modes. The main advantage of the proportional control is that an immediate proportional output is produced as soon as an…
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Pneumatic Actuators
Valves cannot control a process by themselves. Manual valves require an operator to position them to control a process variable. Valves that must be operated remotely and automatically require special devices to move them. These devices are called actuators. Actuators may be pneumatic, hydraulic, electric solenoids or motors. In this article we look at specifically…
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Integral (Reset) Control Systems
Integral (Reset) control Reset/Integral control describes a controller in which the output rate of change is dependent on the magnitude of the input. Specifically, a smaller amplitude input causes a slower rate of change of the output. This controller is termed to as integral controller because it approximates the mathematical function of integration. This integral…
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Feedback Control System
The basic elements of a feedback control system are represented by the block diagram below. The functional relationships between these elements are also shown in the diagram. The block diagram represents flow paths of control signals but do not represent the flow of energy through the system or process. The plant is the system or…
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Principles of Control Systems
A control system is a system of integrated elements whose function is to maintain a process variable at a desired value or within a desired range of values. The control system monitors a process variable or variables, and then causes some action to occur to maintain the desired system parameter. A good example in a…