Magnetic logic circuits for industrial control systems

THE ELEMENTS of automatic control systems may generally be put into three functional categories: 1. Sensing or input elements, which convert external events into useful control signals. 2. Computing elements, which determine the mode of operation of the controlled system on the basis of input information. 3. Machine actuating elements, which convert the electric signals received from the computing elements into actual physical operations. Control systems can be further classified into two general types, analogue and switching. In analogue systems, input signals and output quantities are continuously variable. In switching systems, information is represented by discrete states of electrical or mechanical quantities. Most switching control systems employ a binary representation, in which only two signal levels are distinguished; this permits the use of components which have only two stable states. Relay control systems are the most common binary switching control systems now in use, and information is represented by the two distinct states of the relay contacts. The purpose of this paper is to describe new nonmechanical magnetic elements for use in binary switching control systems.