Direct digital control in the systems of technological process automation

Abstract

In direct digital control (DDC) systems, computers replace traditional analog control devices. Direct digital control systems not only more efficiently perform the functions carried out by analog control devices but also provide new opportunities for increasing control flexibility, such as reprogramming to achieve the required control effects. The principles of developing di-rect digital control systems are described using the example of systems for regulating the tech-nological parameters of rolling. Both analog and discrete automatic control systems (ACS) are used to control mechanisms and equipment at the lower level of the integrated automated con-trol system (IACS) as well as to regulate the technological parameters of rolling. Direct digital control systems built on microprocessor computing technology are widely used. This is basic automation. With traditional control carried out using local automation tools at the lower level of the IACS, each executive mechanism is associated with a separate local system. In a DDC system, a computer operating in a multiplexed time-sharing mode simultaneously regulates several control loops. The computer works on the principle of step-by-step control with a short-term sequential connection to each of the serviced control circuits. It calculates and provides each control loop with new control input values. The main advantages of using DDC systems are listed in the paper. Some algorithms for direct digital control on heavy plate rolling mills and the structure of the algorithm and software of DDC are provided in the article. Some solu-tions regarding the development of DDC systems used for the creation of technological process automation systems at rolling mills are also described.