Use of Digital Analogue Simulator (DAS)

Abstract

Many digital programs have been written with the object of solving sets of differential and algebraic equations representing the behaviour of physical systems. Some of these programs are arranged so that to the user they appear to simulate the behaviour and organization of an analogue computer/ '> Many of these programs are offered as competitors to the analogue computer, and it was, therefore, decided to assess the behaviour of such a program and compare its performance with analogue methods. The latest program available at that time was DAS (digital analogue simulator), which was available from the SHARE library**; this program was therefore used in a computing experiment. The aim was to assess the behaviour of both methods of calculation when applied to the solution of two dynamic problems, a simple problem and a typical complex plant problem, and to see how the results compared, both in accuracy and in time required for solution. In assessing the behaviour of DAS, extensive use was made of the methods of linear control theory, and for this reason the work, which is discussed in this paper, should be of interest to both computing people and to control engineers. It is, however, not so much an application of computers in the study of control systems as an application of control theory in the study of computing processes. This paper was originally presented at a Joint Meeting between the S.I.T. and the B.C.S.