Automatic control is becoming more and more important in this age of automation. In manufacturing processes it ensures that certain parameters, such as temperature, pressure, speed cc voltage, take up specific constant values recognized as the optimum. or are maintained in a particular relationship to other variables. In other words, the duty of control engineering is to bring these parameters to certain predefined values (setpoints), and to maintain them constant against all disturbing influences. Hadvever, this apparently simple duty involves a large number of problems which are not obvious at first glance.
Modern control engineering has links with almost every technical area. Its spectrum of application ranges from electrical engineering, through drives, mechanical engineering, right up to manufacturing processes. Any attempt to explain control engineering by referring to specialized rules for each area would mean that the control engineer has to have a thorough knowledge of each special field in which he has to provide control. This is simply not possible with the current state of technology.
However, it is obvious that there are certain common concepts behind these specialized tasks. It soon becomes clear, for example, that there are similar features in controlling a drive and in pres-sure and temperature control: these features can be described by using a standard procedure. The fundamental laws of control engineering apply to all control circuits, irrespective of the different forms of equipment and instruments involved.
A practical engineer. trying to gain a better understanding of control engineering, may consult various books on the subject. These books usually suggest that a more detailed knowledge of control engineering is not possible, without extensive mathematical knowledge. This impression is completely wrong. It is found again and again that, provided sufficient effort is made in presentation. a clear understanding can be achieved, even in the case of relationships which appear to demand an extensive mathematical knowledge.
The real requirement in solving control tasks is not a knowledge of many formulas or mathematical methods, but a clear grasp of the effective relationships in the control circuit.