Boolean minimization of large relay interlock and control systems

Abstract : The perfection of the transistor and the subsequent birth of a vast digital technology has focused special attention on the methods and mathematics of Boolean algebra. The result of this attention has been the development of powerful methods of synthesis and minimization of logic circuits. The purpose of this paper is to explore the applicability of Boolean minimization methods to the design of large relay interlock and control systems. The investigation of an existing and representative system from the Boolean standpoint was judged the best way to accomplish this purpose. Accordingly, the system selected was the Livermore variable-energy 90-inch cyclotron located at the Lawrence Radiation Laboratory, Livermore, California. The conclusion is that for this class of system a working knowledge of elementary Boolean algebra and an engineer's normal intuition would be sufficient to achieve minimal design. As a bonus result, the symbolic notation known as gate notation was found to be a valuable aid in the representation and understanding of the interlock and control logic of the cyclotron.