Abstract: Included are a connection monitoring unit that monitors the presence of connection with a PLC (Programmable Logic Controller) constituting a PLC system, and that, upon detection of connection with the PLC, acquires data related to the state of the PLC system; a function-selecting-screen display unit that displays a list of functions that can be used for searching for an error according to the state of the PLC system acquired by the connection monitoring unit and receives a function selected from the list; and a function-screen display unit that displays information related to the error acquired by the function selected from the list.

Abstract: An editor-screen display unit configured to cause a display device to display a list of one or more units applicable to a programmable logic controller, a unit-configuration display unit configured to cause the display device to display a model indicating an arrangement state of the one or more units of the programmable logic controller, a unit-selection/arrangement-input detecting unit configured to detect unit selection operation for selecting a unit in the unit list using an input device and unit arrangement operation for designating a CPU unit on the model by operating the input device in a state in which the unit selection operation is maintained, and a management-CPU-determination processing unit configured to determine a CPU that manages the unit selected by the unit selection operation as a CPU included in the CPU unit designated by the unit arrangement operation, are included.

Abstract: A parameter setting device includes reference-format definition data for specifying setting items of a parameter regarding a first unit of a predetermined model and a predetermined version, differential-format definition data for specifying setting items of a parameter regarding a second unit of a model or a version different from the model or the version of the first unit with a difference from the reference-format definition data, a reference-data access unit and a differential-data access unit that select, when a parameter-setting target unit is the first unit, the reference-format definition data, and select, when the parameter-setting target unit is the second unit, both the reference-format definition data and the differential-format definition data, and a parameter conversion unit that interprets the parameter setting data based on the selected format definition data.