| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the load of a process control system and to read time sequential data as fast as possible by preferentially reading time sequential data of a read object from time sequential data stored in a temporary storage means. SOLUTION: The total storage number 14 of the management part 9 of a collection buffer 5 which is read is discriminated to be larger than a storage maximum number 15. When it is larger than the storage maximum number 15, all time sequential data 2 stored in the data part 7 of the collection buffer 5 are read. When the total storage number 14 is smaller than the storage maximum number, the range of the storage area of time sequential data 2, which are not stored in the data part 7 of the collection buffer 5, in time sequential data 2 preserved in a collection file 6 is calculated. Time sequential data 2 preserved in the range calculated in the data part 8 of the collection file 6 is read. Time sequential data of the collection buffer on a storage element can be read much more than time sequential data of the collection file on the auxiliary storage means.</p> |
