MONITORING CONTROLLER, COMMUNICATION SYSTEM, AND SYSTEM SWITCHING METHOD

摘要

PROBLEM TO BE SOLVED: To prevent execution of unintended system switching.SOLUTION: A communication unit 302 of a standby monitoring controller 300 transmits, to all of a plurality of terminal devices as monitoring controlling objects, a communication confirmation command for commanding them to confirm the communication state with an active monitoring controller. The communication unit 302 receives, from each terminal device, a response to the transmitted communication confirmation command. When the communication unit 302 receives a response indicating "impossibility of communication" with the active monitoring controller from all of the terminal devices, a switching unit 303 of the standby monitoring controller 300 determines that an abnormality occurs in the active monitoring controller, and performs switching from the standby to the active.