Abstract
The authors propose a methodology to transform the C/E system to the Mark Flow Graph (MFG) equivalent in the meaning of occurrence series of events.
It is well known that the C/E system is used effectively to represent the specification of the complex sequential control systems having the parallelism and conflict. On the other hand, the MFG was proposed as the extended C/E system to precisely represent the control algorithm. Therefore, it is necessary to convert the C/E system to the corresponding MFG as a control algorithm suitable to controllers to be adopted. In this process, no matter which kind of control algorithms (the Petri net type or the ladder type) are to be deduced, to eliminate the dummy conditions in the C/E system, is necessary to simplify the algorithm and also to deduced the hard-wired control systems.
For this purpose, replacing all conditions in the C/E system to logic variables (condition variables), the condition logic equations based on the minimum support are introduced to obtain dummy conditions as the logic functions of the other conditions. Substituting them to the event enabling equations, the dummy conditions are eliminated from the original C/E system and the equivalent MFG is obtained. Examples reveal the straightforward procedure of the transformation of the C/E system to the MFG.
