SYSTEM FOR SPECIFYING VARIATION FACTORS OF FINISHED PLATE THICKNESS IN ROLLING MILL

PURPOSE:To quickly specify the factor of variation by monitoring the variation of the plate thickness continuously on the inlet and outlet sides and perceiving the variation of the plate thickness on the outlet side at the initial stage. CONSTITUTION:Plate thickness indicators 1, 2 to measure the respective thicknesses of a rolled plates, fast Fourier transform devices (F, F, T) 3, 4 to analyze time series signals of plate thickness from these plate thickness indicators 1, 2, and computers 5, 6, 7 wherein a peak frequency of the plate thickness variation is required from a difference between a frequency element signal transformed by an outside frequency analyzer and a frequency element signal transformed by an inlet side frequency analyzer, a variation frequency which variations of each roll 10a-14a, 10b-14b of the rolling mill influence to the plate thickness on the outlet side is calculated and these peak frequency and variation frequency are compared to continuously monitor the abnormal variation of the plate thickness and to specify the factors of the variation are provided respectively on the inlet and outlet sides of the rolling mill.