Anomaly monitoring device and method for producing anomaly signs according to combinations of sensors based on relationship of sensor fluctuations

A monitoring device configured to monitor a control subject according to output signals of a plurality of sensors each configured to detect a state of the control subject,

• the plurality of sensors including a combination of a subject sensor and its related sensor, the monitoring device comprising a processor and a memory configured to store instructions, the processor executing the instructions to implement:
• a first calculation unit configured to calculate a relationship fluctuation level representing a relationship between a fluctuation of the subject sensor and a fluctuation of the related sensor for each combination of the subject sensor and its related sensor;
• a second calculation unit configured to calculate an anomaly sign level by summing up the relationship fluctuation level for all combinations of the subject sensor and its related sensor;
• and
• a management unit configured to identify the combination of the subject sensor and the related sensor with the relationship fluctuation level higher than a threshold indicating a collapse of the relationship and to thereby calculate a number of appearances of the subject sensor and the related sensor included in the identified combination, thus producing first anomaly sign information representing the number of appearances for each sensor.