The article presents an automated control system for a screwdown mechanism of a laboratory rolling mill DUO-130 developed by NPI 'Practice Equipment and Technologies', SUSU (NRU). A specific feature of the system under consideration is its integrity into control system of the whole rolling mill. The article describes the operating principle of a screwdown mechanism regulated by a step motor and advantages of the chosen control method. It also gives the structure and operating principle of the control system of a servo drive that ensures regulating of a screwdown mechanism. It also presents the process of calculating the determination precision and positioning the upper roller of a roller plate.