Abstract: A rolling control device (10) updates a preset load value Pset based on operation actual results at timings ta to tb. The rolling control device (10) derives a plasticity coefficient Qchk based on operation actual results at timings tb to tc. When the determining that it is necessary to re-update the updated preset load value Pset based on the plasticity coefficient Qchk, the rolling control device (10) updates the preset load value Pset again based on the operation actual results at the timings tb to tc.

Abstract: A plant control system includes a process computer (1) managing a plant, a PLC (2) interposed between the process computer (1) and equipment (3) of the plant, and a general-purpose PC (7) executing arithmetic processing based on arithmetic data received from the PLC (2) and transmitting arithmetic result data thereof to the PLC (2). The functions are divided such that sequential control logic is executed by the PLC (2) and complicated arithmetic processing is executed by the general-purpose PC (7), and the arithmetic result data outputted from the general-purpose PC (7) always passes through the PLC (2) so that consistency of the arithmetic result data is checked in the PLC (2).

Abstract: A plant control system includes a process computer (1) managing a plant, a PLC (2) interposed between the process computer (1) and equipment (3) of the plant, and a general-purpose PC (7) executing arithmetic processing based on arithmetic data received from the PLC (2) and transmitting arithmetic result data thereof to the PLC (2). The functions are divided such that sequential control logic is executed by the PLC (2) and complicated arithmetic processing is executed by the general-purpose PC (7), and the arithmetic result data outputted from the general-purpose PC (7) always passes through the PLC (2) so that consistency of the arithmetic result data is checked in the PLC (2).