Takao Kokubu

Application of powerful SFC language (HI-FLOW) to FA systems in a tire industry

A sequential function chart (SFC) language, HI-FLOW, has been developed mainly for automatic sequential machine control for factory automation (FA) systems in a tire manufacturing plant. The combination of HI-FLOW and ladder logic in FA environments provides advantages over pure ladder logic control. HI-FLOW has a distinct effect on machine controllability, requires less design and maintenance manpower, reduces program and documentation size, erases checkout and start-up work, and saves training time for new personnel.<<ETX>>

Application of powerful SFC to self diagnosis of manufacturing machines in the tire industry

Proposed new troubleshooting methods for programmable controllers (PCs). Through studies of field applications in the tire industry the sequential function chart (SFC) is recognized as not only a powerful substitution for ladder logic diagram but also as useful in machine trouble diagnosis. Typical enhancements of SFC as self diagnostic function are; 1) to search the conditions which cause the machine to halt, 2) to collect logging table data for the historical program paths analysis, and 3) to specify the cause of the trouble by tracing back 1) and 2). This paper discusses the self diagnostic functions by SFC and its implementation.<<ETX>>