US Patent 7757025 Programmable logic controller peripheral device and program creation method thereof

A peripheral device for a programmable logic controller according to the invention includes: an instruction table for correlatively storing instructions and the input/output types of parameters for the instructions; a search/discrimination means for searching the instruction table for an instruction in a code in a portion of a sequence program selected as diversion data from an existing diversion-source sequence program, to discriminate the input/output type of a parameter for the instruction; a search result creating/storing means for creating and storing a search result table by combining an address in the code in the selected portion of the sequence program, with the input/output type; a component data creating means for creating a variable data table by replacing the input/output types stored in the search result table with variable names, and for creating component data by adding the corresponding variable names to variables and to circuit information; and a component data diversion means for diverting the component data into an arbitrary position in a designated sequence program.