PLANT OPERATING DEVICE

PURPOSE:To speedily perform recovery work and to reduce the labor of an operator as well by informing the operator of a defective input point name and a control logic name when the plant data of an input point to be used for the arithmetic of a control logic are defective. CONSTITUTION:A control logic input point preserving part 13 previously extracts and preserves an operation item and an input point name for each operation timing condition to be used for the control logic of an arithmetic processing part 6. When there is abnormality in the plant data fetched into an input processing part 5, a deciding processing part 12 fetches that input point name, retrieves whether the fetched input point name is used for the control logic input point preserving part 13 or not, extracts the operating item corresponding to that input point name when it is used, and informs an external output processing part 7 of it. Thus, when the operation timing of the control logic of the arithmetic processing part 6 is abnormal, the abnormal plant data can be reported to the operator.