1997 Volume 117 Issue 12 Pages 1432-1440
Material Handling System (MHS) is a kind of typical sequential control systems and also an important part of Factory Automation (FA) or Computer Integrated Manufacturing (CIM). The control of MHS is usually performed by Programmable Controllers (PCs) and its description depends on the PCs used. Ladder Diagram (LD) is widely used as a description method of PCs in sequential control systems. In recent years, a new description method called Sequential Function Chart (SFC) is also used in some PCs on the market. In order to apply SFC to MHSs, the authors have already proposed a representing manner called Total-SFC (T-SFC) which consists of SFC, Random Function Chart (RFC) and Interlock Table. Its part of SFC describes sequential control, while RFC and Interlock Table represent extraordinary and emergency processes. In other words, T-SFC offers a technique to describe not only the part of sequential control but also the part of non-sequential control of MHSs. In this paper, we describe the implementation of T-SFC for a general PC in which SFC and LD can be utilized. This paper presents a translation method from T-SFC to widely utilized PC's programs through the use of a T-SFC functional structure tableau, and verifies the validity of the proposed translation method with the demonstration of a simple case study. And, we also discuss the practicability of this T-SFC based approach in comparison with the conventional LD approach and point out the efficiency of T-SFC.