A configuration of a control device capable of efficiently operating multiple types of programs in different execution formats on a single control device is provided. At least a first task that has a first priority including processing execution performed by a program execution part and a command calculation part, a second task that has a second priority, lower than the first priority, including processing execution performed by a parsing part, and a third task that has a third priority including execution of a processing content different from the first task and the second task are set in a scheduler. The control device further includes a priority changing part monitoring a processing state of the parsing part, and when the processing state of the parsing part meets a predetermined condition, changing the second priority set to the second task corresponding to the condition.

A system program includes a procedure library in which at least a procedure for controlling execution of a control program and a procedure for controlling output of output data and input of input data are included. If schedule-building data including execution order specifications for the procedures included in the procedure library is stored in a storage section, the system program causes a microprocessor to execute the procedures included in the procedure library in accordance with the procedure execution order specifications included in schedule-building data.

A control device is provided with a task execution unit, a collection unit which collects variables which have been referenced and updated in a user program and a management unit which manages the collected variables. The user program includes a collection instruction program which instructs the collection of the variables by the collection unit. The collection instruction program further includes distinguishing information for a user to distinguish the location of the collection instruction program in the user program. When the collection of the variables has been instructed by the collection instruction program, the management unit associates the variables collected by the collection unit with the distinguishing information of the collection instruction program.

A control system includes a control unit, a transmission unit, an application execution unit, and an arbitration unit that arbitrates a data set exchanged between the transmission unit and the application execution unit. The arbitration means includes a first acquisition unit that acquires information about pieces of process data managed by the control unit, a second acquisition unit that acquires information about an application executed by the application execution unit, a determination unit that determines process data to be included in a data set based on the information about the pieces of process data acquired by the first acquisition unit and the information about the application executed acquired by the second acquisition unit, and a notification unit that notifies each of the transmission unit and the application execution unit of a content of the process data to be included in the data set determined by the determination unit.

A scheduler causes a microprocessor to start execution of a first control program after a communication circuit transmits output data and receives input data in a control cycle following a control circle in which execution of the first control program has ended, and causes execution of an unexecuted portion of the first control program in a control cycle following a control cycle in which execution of the first control cycle has not ended.

A controller stores link information linking a predetermined event to a variable associated with the event. The controller stores first log information in association with time information into a memory in response to occurrence of the predetermined event. The first log information includes information about the event, and a current value of a predetermined variable associated with the event included in the link information. The controller stores second log information in association with time information into a memory in accordance with a predetermined period. The second log information includes information about a value of the predetermined variable. An information processing device obtains the link information from the controller, and displays information indicating the variable associated with an event indicated by the first log information onto the monitor-based on the link information and the second log information.