MODELLING SYSTEM SPECIFICATIONS ON A FINITE STATE MACHINE

Abstract

CODE (COntrol DEfinition language) is a formal language designed and used for implementation of control strategies in sequence control applications, such as found in industrial control. CODE treats processes as finite state machines (FSM), by defining transition conditions that determine when a state change will occur, and the consequent transition action. A control definition consists of a hierarchical model, each layer of which consists of a number of FSMs. The CODE concept is proposed for use in a formal specification language, that would form part of a specification work bench, including syntax-checking editors, consistency and completeness checks, automatic simulation and documentation systems. This work bench will provide a powerful tool for specification and development of process control and other systems. It will help increase the effectiveness of software designers and engineers; it will also contribute to increased formality in system specification, helping to eliminate a major source of error.