Direct Digital Control
| Autor: | Om Prakash Bharti |
|---|---|
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | IOSR Journal of Electrical and Electronics Engineering. 7:06-10 |
| ISSN: | 2278-1676 2320-3331 |
| DOI: | 10.9790/1676-0740610 |
| Popis: | With the advent of digital computers the engineers felt the need of utilizing computer advantages in the industrial process through the centralized control system. This thought led to the introduction of direct digital control (DDC) phylisophy. In this paper the author has presented a brief review of the structure of DDC as well as its working with illustration. The two types of algorithm used for programming as PID controller are discussed. The author has also pointed out the merits of DDC over analog control.Besides a few practical application has also been described. With the introduction of computers, engineers felt the need of utilizing computer advantages in instrumentation field through centralized control system. These advantages were optimization, alarm and logging function, historic analysis, trending, sequence control and self diagnostic techniques. This gave birth to Direct Digital Control phylisophy in instrumentation with a back up of analog control system. In 1962, Imperial Chemical Industries (ICI) in England replaced complete analog instrumentation for process control by a Ferranti Argus computer. The computer considered 224 variables and controlled 129 valves directly. The name direct digital control (DDC) was coined to emphasize that the computer directly controlled the processes. DDC i.e. Direct Digital Control is a method of process control in which computer is an integral part of the loop. It essentially consists of microprocessor / pc / computer based controllers and the control logic is performed by software. It is also known as "Loop Control" as the computer which provides the functions of cmparator, controller, limiting and other safeguarding operations, is conneted in the feedback loop. |
| Databáze: | OpenAIRE |
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