Control system, relay device, and relay program

A control system comprising:

• a controller;
• a management unit;
• and
• an application execution unit,
• wherein the controller includes:
• a control unit configured to execute a control program controlling a control target, and manage a plurality of pieces of process data referred to or updated in the control program;
• and
• a communication processing unit configured to be capable of transmitting a plurality of data sets including values of the plurality of pieces of process data managed by the control unit, each of the plurality of data sets including one or a plurality of predetermined process data values,
• wherein:
• the application execution unit is configured to execute one or a plurality of applications using the value of the process data included in the data set transmitted by the communication processing unit,
• the management unit is configured to determine a data set validating transmission in the plurality of data sets transmittable by the communication processing unit according to the application executed by the application execution unit,
• the data set validating transmission corresponds to a data set for which the management unit requests the communication processing unit to transmit,
• the one or a plurality of applications includes a first application and second application,
• the plurality of pieces of process data include first process data necessary for executing the first application and second process data necessary for executing the second application,
• the management unit is configured to update validity and invalidity information for determining transmission to start and transmission to stop of each of the plurality of data sets according to the application executed by the application execution unit,
• when receiving a start request to transmit the first process data from the application execution unit, the management unit refers to a data set list capable of specifying a type of process data included in each data set, and updates the validity and invalidity information so that a corresponding first data set indicates a transmission start state, and after that, transmits a first start request for requesting a start of transmission of the first data set to the communication processing unit,
• when receiving the first start request, the communication processing unit starts a process of repeatedly transmitting the first data set,
• when changing the application to be executed from the first application to the second application in response to a user operation, the application execution unit transmits a stop request to stop the transmission of the first process data to the management unit, and after that, transmits a start request to transmit the second process data necessary for execution of the second application to the management unit,
• when receiving the stop request to stop the transmission of the first process data from the application execution unit, the management unit refers to the data set list, and updates the validity and invalidity information so that the corresponding first data set indicates a transmission stop state, and after that, transmits a first stop request for requesting a stop of the transmission of the first data set to the communication processing unit,
• when receiving the first stop request, the communication processing unit stops the process of repeatedly transmitting the first data set,
• when receiving the start request to transmit the second process data from the application execution unit, the management unit refers to the data set list, and updates the validity and invalidity information so that a corresponding second data set indicates a transmission start state, and after that, transmits a second start request for requesting a start of transmission of the second data set to the communication processing unit, and
• when receiving the second start request, the communication processing unit starts a process of repeatedly transmitting the second data set.