PURPOSE: To extract time series data of numerical values assuming hunting by a method wherein the time series data of a process data is divided into a plurality of data with an overlapped time zone, and each time series data is analyzed according to FFT(Fast Fourier Transform).
CONSTITUTION: Data of each sensor of a target plant is collected by a data collecting mechanism 2 via a process input/output device 1, written into a plant database 5 and transferred to a historical database 6 periodically for preservation for a long time. The content in the bases 5 and 6 is easy to be referred to via a man-machine mechanism 3. A process controlling/processing mechanism 4 operates and processes the collected process data. The mechanism 4 calculates the deviation and the changing ratio of the process data from the previous process data, to check if the process data exceeds a set value and so on. The mechanism 4 outputs an alarm warning to the mechanism 3 depending on the checking result and displays at a CRT 21.
KAWAGUCHI KOICHI
KOYAMA KAZUO
NAKAMURA KENJI
TOKYO GAS CO LTD
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