Automatic control in industry
Any technical development that enables a machine or instrument to dispense with labour is a step toward automation. Wherever two or more automatic machines are tied together with overriding automatic control to create a self-feeding, self-initiating and self-checking process, an automated system is created. The real distribution is between automation that displaces muscle and automation that displaces brain, and it is roughly the same distinction as that between automatic operation and automatic control. The industrial development of the nineteenth century was a change towards automatic operation. But mechanization was limited to individual processes, and only in a few trades it was possible to provide automatic links between processes and organized production as a continuous flow. In the twentieth century the idea was widely applied of producing goods in a continuous flow rather than in batches. The control was obtained by a human operator who noted faults and deviations and corrected them either directly or through instruments. Control may be simply mechanical, electrical, electronic or a combination.
The developments in automatic operation while extending their application, were not revolutionary but part of a well-established trend. Those in automatic control have been considerably more drastic, and arose largely from the recent and sudden application of electronic methods of control. Electro-mechanical, pneumatic and hydraulic devices also contributed, but the introduction of electronic computers marked the new stage in the development of automatic control. The electronic devices rapidly gained in importance and industrial enterprises widely used them to plan and control the operations of machines. These devices can detect faults in a processed part, communicate the error to the machine and adjust its operation so as to correct the fault. They can integrate the work of industrial- machines and the more complex devices can select alternative courses of action according to the instructions fed into them, considerably extending the possibilities of remote control. Now electronic devices greatly reduced the amount of routine brainwork performed at factories. Rapid technological advance reduced the part played by human labour to skilled supervision and maintenance. Electronic computers have shown that man can rely on them for the performance of operations based on formal logic.
Automatic systems take several forms and are based on several different techniques, but in each case the measurement and correction of errors are performed and coordinated by electronic devices and the human operator does not take an active part in it.
First of all automatic control was widely established in such industries as chemicals, petroleum, iron and steel, cement, paper, textile, printing, food and others. The overall trend now is toward a total automatic control in industry with the help of new generations of electronic devices with their rapidity, accurateness, reliability, flexibility, and compactness.
The present day stage of automation is based on the revolution in computer technology, in computerisation of the whole national economy.
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