Abstract: A programmable controller capable of checking accessible signal addresses for each of ladder programs is provided. The programmable controller includes signal address setting extraction means for extracting an available address setting table from each of the ladder programs; a signal address overlap determination section for determining whether there is an overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs, based on the available address setting tables extracted by the signal address setting extraction means; and a ladder program execution section for executing the plurality of ladder programs if the signal address overlap determination section determines that there is no overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs.

Abstract: A program comparing device that compares programs described by ladder diagrams includes: a logical expression converting unit configured to convert a ladder circuit of the program into a logical expression, in units of the ladder circuit; an order converting unit configured to rearrange an order of variables of the logical expression of at least one ladder circuit, of two of the ladder circuits that are comparison targets, so as not to change a result of the logical expression; and a comparing unit configured to compare the logical expression of the one ladder circuit after the order of the variables has been rearranged, with a logical expression of another ladder circuit of the two of the ladder circuits, and judge whether or not they match.

Abstract: A ladder diagram monitoring device displays an operation situation of a ladder program executed on a programmable controller built in a CNC on a monitor. A comment added to a circuit of the ladder program is provided with a region for displaying information on an operation situation of the CNC, the operation situation of the ladder program is reflected in the region, and display data in which the operation situation of the CNC is displayed is displayed.

Abstract: A programmable controller capable of checking accessible signal addresses for each of ladder programs is provided. The programmable controller includes signal address setting extraction means for extracting an available address setting table from each of the ladder programs; a signal address overlap determination section for determining whether there is an overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs, based on the available address setting tables extracted by the signal address setting extraction means; and a ladder program execution section for executing the plurality of ladder programs if the signal address overlap determination section determines that there is no overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs.

Abstract: A ladder diagram monitoring device displays an operation situation of a ladder program executed on a programmable controller built in a CNC on a monitor. A comment added to a circuit of the ladder program is provided with a region for displaying information on an operation situation of the CNC, the operation situation of the ladder program is reflected in the region, and display data in which the operation situation of the CNC is displayed is displayed.