Abstract: Provided is a control device for a control system with a dual clock synchronization mechanism which detects a clock synchronization problem resulting from various circumstances of a site to analyze a situation related to the clock synchronization problem and warn of the situation. Therefore, it is possible to efficiently handle a clock synchronization problem resulting from various circumstances of a site.

Abstract: A control system for monitoring and taking action on security, abnormal situations, abnormal operations, and the like in various fields is disclosed. The present control system includes a user computing unit and a secure computing unit. The user computing unit includes its own CPU and generates control information by executing a user program. The secure computing unit includes its own CPU and again checks input information inputted from a device to be controlled and the control information generated by the user computing unit to generate system check information. The system check information is compared with system state determination standard information preset by a user, and when the system state is within a normal range, the control information is outputted as it is, and when the system state is not within the normal range, the user takes a preset appropriate security action.