A Description of ^|^ldquo;Return Action^|^rdquo; of Automatic Machines by Total Sequential Function Chart and Its Application to the Control
Satoru YOKOI, Iko Miyazawa, Takashi Sekiguchi · Transactions of the Society of Instrument and Control Engineers · 1997
Automatic machine which seems to be represented by transfer machines takes charge of manufacturing process and its automation is important for realization of automation of whole manufacturing system. Manufacturing process of automatic machines is generally sequential control and Programmable Controller (PC) is put to controlling use. During automatic driving, automatic machines frequently carries out a special so-called “return action” which is a kind of controlled action with reverse sequence according to its normal sequence. It is difficult to represent “return action” by Sequential Function Chart (SFC) which is widely used for the normal sequential control. Some representing techniques are already suggested, but a practical case is not appeared for the simplicity of SFC expression to be ruined.The authors suggested Total-SFC (T-SFC) as an expansion of SFC expression. In T-SFC, sequential control part is represented in usual SFC while non-sequential control part is represented in Random Function Chart (RFC) and Interlock Tables. The change over from sequential control to reverse sequential control of “return action” is non-sequential control and reverse sequential control itself is sequential control. In this paper, the general definition is given for “return action” having such characteristics. An approach by T-SFC is taken and the effectiveness of the representation is shown. That realization is possible by exemplifying in an example of transfer machine and the advantage is described.