Abstract
In this paper, the methods of “Quantitative Analysis of Process Lags” developed in a previous paper are extended to include automatic control. Carrying on the idea of representation by liquid-level systems, a specific system is postulated as a model for a typical industrial process which may or may not be thermal. Continuing the quantitative approach, the mathematical machinery is demonstrated by which the operation of control on processes may be investigated. A selected succession of controllers, characterized by the laws of control which govern them, are considered in connection with their performance on the model system. Although no attempt has been made to formulate rules governing the proper application of the various types of controllers considered or governing the adjustment of any of these individual types, the authors consider that analyses of this sort may well serve as a guide to practical theorems in a technology of automatic control.
