Design of PLCs for automated industrial systems based on discrete event models

Ladder diagrams (LDs) have been widely used in industrial control systems as a programming language for programmable logic controllers (PLCs). However, the synthesis of LD itself mainly depends on the experience of the industrial engineer, which often results in unstructured or inflexible design. Hence, in this paper, we propose a ladder diagram transformation (LDT) algorithm which systematically produces LDs for PLCs based on discrete event models (DEMs) to enhance the structured and flexible design mechanism. Moreover, the LDT algorithm is convenient and easy to be implemented. The LDT algorithm is illustrated by considering the control of a point to point (PTP) control system.