Design of modular and distributable automation software for PLCs

Abstract

Design and maintainability of modular automation software are common concerns nowadays. Common practice in industry usually overlooks the design phase of software, jumping directly into the coding phase, which typically results in poorly readable and maintainable code. In this work, it is shown how modular and hierarchically structured design of discrete event control systems, which is supported by Grafcet models, can be subsequently implemented in several devices distributed across the fieldbus. Besides, the resulting software is more readable and maintainable due to its similarities with the proposed Grafcet model. An example is provided showing how a distributed application can be tested in a centralized fashion.