Plant diagnosis device

Standard data approximately defined are inputted as 1:1 functional data between at least two or more plant data and each of plant data are inputted. Diagnosis data corresponding to each of process data are formed based on the functional data. Limit value data to be a threshold value which determines whether the diagnosis data are in a predetermined state or not are formed. The diagnosis data and the limit value data are displayed in a recognizable state. If diagnosis data of a plurality of plants are displayed simultaneously, all of the plant data are substantially the same value with one standard datum if the plant is in a normal state. When abnormality should occur in the plant, the difference between the diagnosis data and the standard data is remarkable, and the difference between the diagnosis data of other normal plant data and the standard data are also made remarkably, accordingly, the display of a plurality of diagnosis data is scattered thereby capable of diagnosing the abnormality of the plant. (N.H.)