Method for programming a PLC using relay ladder logic

摘要

The procedure involves activating a downstream switch network (30) of an application program to be subordinated to an upstream switch network (10) and to state of a contact zone (20). A line (19,39) of each network is made of a combination of switches (15,16,35,36,37) acting on multiple coils (11,31,32). Ends of the switches are connected to two connecting columns (5,6). The column (5) has the zone between the two networks. An independent claim is also included for automatic equipment having a processing unit executing an application program according to a programming procedure.