| 摘要 |
PROBLEM TO BE SOLVED: To suppress unnecessary dispatch of a maintenance engineer for a communication failure between a master station and a slave station or relay station.SOLUTION: A master station 10 comprises: a processing unit 12 for detecting a station related to unreceived information, as an abnormal station, by determining whether or not information from slave stations 20, 30 and 40, and relay stations 50, 60 and 70 are received correctly according to an information acquisition schedule; a determination unit 12d for determining which time zone of a plurality of preset time zones corresponds to a period in which the abnormal station has been detected; a determination unit 12e for determining whether or not the number of times of detecting the same station as an abnormal station in the same time zone reaches a prescribed number of times; a processing unit 12h which sets a period for information request for a station whose number of times of detection has not reached the prescribed number of times, to a normal period, and sets a period for information request for a station (cautionary abnormal station) whose number of times of detection has reached the prescribed number of times, to a special period longer than the normal period; and a determination unit 12i for determining whether or not a frequency of the cautionary abnormal station being detected as an abnormal station in the same time zone has reached a prescribed frequency. The master station 10 transmits a command for dispatching a maintenance engineer to the cautionary abnormal station to a dispatch base 90, only when the frequency has reached the prescribed frequency. |
