CONTROL SYSTEM, RELAY DEVICE, AND CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a technique that guarantees at low cost that an order is performed under a prescribed condition when a control monitoring system in which an information system and a control system are connected controls and monitors a control and monitoring object.SOLUTION: A control system includes: a control device that performs at least one of control and monitoring of a control object; a computer that performs processing involving control or monitoring; and a gateway device that relays a communication message between the control device and the computer. The gateway device obtains a prescribed state index related to a first communication message when receiving the first communication message from the computer, determines whether or not a prescribed execution condition is met on the basis of the state index, transmits a second communication message based on the received first communication message to the control device if the execution condition is met, and does not transmit the second communication message to the control device if the execution condition is not met.