Abstract: Information processing system including pluralities of first and second equipment items, and a third equipment item. Each first equipment item stores history data and returns a first response block about controls and changes in status of each first equipment item, responsive to a data request from the second equipment items. Each second equipment item stores the history data returned responsive to the data request; a second response block returns history data stored in the second history storage block responsive to a request from the third equipment item; first and second lists store first information identifying latest history data returned from the first equipment items regarding each first equipment item, and second information identifies history data last returned to the third equipment item regarding each first equipment item. Third equipment item's third history storage block stores history data returned responsive to the data request made to the second equipment items.

Abstract: Information processing system including: a plurality of process control units storing process data including present value and time-series data or historical data, and a plurality of data collection units collecting and processing data from the process control units. The data collection units each include: a first dynamic management section managing access and exit of the data collection unit of interest to and from the information processing system and managing operating status of all data collection units currently accessing the information processing system; a second dynamic management section managing addition and removal of process control units to and from the information processing system; and a charge determination section determining process control units to be taken charge of by the data collection unit of interest based on first identification information allocated to each of the data collection units and on second identification information allocated to each of the process control units.

Abstract: Information processing system including pluralities of first and second equipment items, and a third equipment item. Each first equipment item stores history data and returns a first response block about controls and changes in status of each first equipment item, responsive to a data request from the second equipment items. Each second equipment item stores the history data returned responsive to the data request; a second response block returns history data stored in the second history storage block responsive to a request from the third equipment item; first and second lists store first information identifying latest history data returned from the first equipment items regarding each first equipment item, and second information identifies history data last returned to the third equipment item regarding each first equipment item. Third equipment item's third history storage block stores history data returned responsive to the data request made to the second equipment items.

Abstract: Information processing system including: a plurality of process control units storing process data including present value and time-series data or historical data, and a plurality of data collection units collecting and processing data from the process control units. The data collection units each include: a first dynamic management section managing access and exit of the data collection unit of interest to and from the information processing system and managing operating status of all data collection units currently accessing the information processing system; a second dynamic management section managing addition and removal of process control units to and from the information processing system; and a charge determination section determining process control units to be taken charge of by the data collection unit of interest based on first identification information allocated to each of the data collection units and on second identification information allocated to each of the process control units.