Modem manufacturing systems have challenged the use of LDs for PLCs to &sign their discrete-event controllers. Researchers are constantly pursuing integrated tools that eliminate the limiiaiions of LDs. fiese fools are aimed not only for control but also for system anabsis, mahation, and simulation. For the past decadq Petri nets (PN) have emerged m an imporiant tool to provide an integrated solution for modeling, analysis, simulation, and control of indush'al automated systems. Different types of PN-based controllers in the academia are intended to apply in the industy. There is a need for more benchmark studies of PN andLD m e t h d in order fo fern a sirucfuredand integrated framework for logic control software development. This paper surveys the recently reported work on these melhoh with focus on the conversion methods between PNs and LDs.