A matrix method for the design of relay circuits

IN THIS PAPER we shall be concerned first with multiple-output combinational relay switching circuits, that is, circuits which may be represented symbolically as in Fig. 1. The n coils X1, X2, ¿, Xn determine respectively the conditions x1, x2, ¿, xn of the contacts in the box. We call x1, x2, ¿, xn the input variables of the circuit. The output variables are the interconnections between the terminals 1, 2, ¿, p resulting from energization of certain of the coils. It is assumed that the coils are controlled independently of the circuitry in the box. It is this absence of feedback that makes the circuit ¿combinational.¿