HISTORY DATA PROCESSOR

PURPOSE:To reduce the quantity of history data that should be stored for a long period and to shorten the retrieving time of the history data. CONSTITUTION:A history data processor consists of a plant data collector means 1, a primary history data storing/processing means 3 which stores the collected plant data in a short-time history data file 5, and a secondary history data storing/processing means 7 which changes a short period to a long period for the plant data that passed a fixed period and stores these data in a long- period 1-history data file 9 from the file 5. Furthermore a third history data storing/processing means 11 is added to set a long period for the plant data that passed another fixed period and store these data in a long-period 2-history data file 13 from the file 9, together with a history data retrieving means 15 which inputs the retrieving request of an operator via a retrieving request input means 17 and retrieves the history data, and a retrieving result output means 19 which outputs the retrieving results of the means 15 to an interactive device 21 or an output device 23.