A control system for controlling a control target, comprising: a master apparatus including a calculation unit and a communication processing unit; and one or more slave apparatuses connected to the master apparatus via a network, wherein the communication processing unit is configured to manage cyclic transmission, on the network, of a data sequence containing data that is handled by the master apparatus and the one or more slave apparatuses, the calculation unit is configured to repeatedly execute output processing and input processing in a predetermined execution cycle, and to repeat program execution processing during a time period when the output processing and the input processing are not executed, the input processing including processing for updating input data in accordance with information that is collected from the control target by the one or more slave apparatuses, and the output processing including processing for generating output data that includes an execution result of the program execution processing, and the communication processing unit is configured: to start cyclic transmission of a first data sequence containing the output data for the one or more slave apparatuses in conjunction with execution of the output processing with the calculation unit; and to start, a predetermined time period before execution start of the input processing with the calculation unit, cyclic transmission of a second data sequence for obtaining information collected by the one or more slave apparatuses from the control target; wherein both the first data sequence and the second data sequence include a command for obtaining information from the one or more slave apparatuses and the output data. a master apparatus including a calculation unit and a communication processing unit; and one or more slave apparatuses connected to the master apparatus via a network, wherein the communication processing unit is configured to manage cyclic transmission, on the network, of a data sequence containing data that is handled by the master apparatus and the one or more slave apparatuses, the calculation unit is configured to repeatedly execute output processing and input processing in a predetermined execution cycle, and to repeat program execution processing during a time period when the output processing and the input processing are not executed, the input processing including processing for updating input data in accordance with information that is collected from the control target by the one or more slave apparatuses, and the output processing including processing for generating output data that includes an execution result of the program execution processing, and the communication processing unit is configured: to start cyclic transmission of a first data sequence containing the output data for the one or more slave apparatuses in conjunction with execution of the output processing with the calculation unit; and to start, a predetermined time period before execution start of the input processing with the calculation unit, cyclic transmission of a second data sequence for obtaining information collected by the one or more slave apparatuses from the control target; wherein to start cyclic transmission of a first data sequence containing the output data for the one or more slave apparatuses in conjunction with execution of the output processing with the calculation unit; and to start, a predetermined time period before execution start of the input processing with the calculation unit, cyclic transmission of a second data sequence for obtaining information collected by the one or more slave apparatuses from the control target; wherein both the first data sequence and the second data sequence include a command for obtaining information from the one or more slave apparatuses and the output data.