METHOD AND DEVICE FOR DIAGNOSING PLANT ABNORMALITY

摘要

PROBLEM TO BE SOLVED: To provide a device and a method for automatically updating the diagnostic reference value of a diagnostic device in the past in the processing of updating the diagnostic reference of the device at the time of highly reliably diagnosing abnormality. SOLUTION: Whether or not it is a diagnostic reference value updating day is confirmed first. In the case that it is not the updating day, this processing is ended. In the case of updating it, after a plant data fetching processing, a prediction operation expression is calculated by using a polynomial approximate expression from the diagnostic reference value in the past and a present value. From the prediction operation expression, the diagnostic reference predicted value of the next diagnostic reference day is calculated. Thereafter, a difference between the diagnostic reference value at present and the next diagnostic reference value is calculated. In the case that the difference exceeds a fixed amount, the diagnostic reference value at present is updated on the basis of the predicted value of the next diagnostic reference value and this processing is ended. Also, in the case of not exceeding the fixed amount, the present diagnostic reference value is not updated this time and diagnosing is performed in the setting until the next updating.