A PLC Circuit Design Education of Complicated Operation in Production Facilities

PLC (Programmable Logic Controller) is widely used for controlling a production facility in order to realize a predetermined operation by integrating many detecting devices and driving devices. The basic function of the PLC is to program a causal relationship between input and output in a relay circuit form called a sequence diagram and to execute this function. It is known that problems of individual differences and malfunctions tend to occur during design of relay circuits, and we have devised ways to solve this problem for years. In this paper, we introduce an education program to construct PLC circuits of complicated operation using “Trigger/Action chart” , “Step-connected sequential circuit” and “Control block diagram” implemented at our training institute.