Abstract
Modern manufacturing systems have challenged the use of LDs for PLCs to design their discrete-event controllers. Researchers are constantly pursuing integrated tools that eliminate the limitations of LDs. These tools are aimed not only for control but also for system analysis, evaluation, and simulation. For the past decades, Petri nets (PN) have emerged as an important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. Different types of PN-based controllers in the academia are intended to apply in the industry. There is a need for more benchmark studies of PN and LD methods in order to form a structured and integrated frame, work for logic control software development. This paper surveys the recently reported work on these methods with focus on the conversion methods between pars and LDs.