| 摘要 |
PURPOSE:To improve the reliability of data transfer while simplifying a whole system. CONSTITUTION:The state of production facilities 1 is monitored by the production history data generating part 4 of a production history managing device 2, and the change of the state of that production facilities 1 is recognized, and production history data including the time information of the time of the occurrence of this change is generated, and is stored successively in a production history data buffer 5 in the order of the oldness of the time information. A read-out request frame FR including the time information for specifying the production history data from what time is wanted is issued from a host computer 3 to the production history managing device 2 as occassion calls. An answer processing part 6 having received the read-out request frame FR retrieves the production history data buffer 5 in accordance with that request condition, and answers to the host computer 3 by generating readout answer data FA capable of being answered by the transmission of one time. |
