Classification of control systems there are three ways: by automatic classification methods in order to participate in the control mode classification, to adjust the law category.One way to control category 1, the open-loop control system if the computer output of open loop control system to exercise control of the production process, but the control results --- the state of the production process does not affect the computer control systems, computer \ controller \ production and other sectors does not constitute a closed loop, is called open-loop control system computer. the production process of the state is no feedback to the computer, but by the operator to monitor the status of the production process, decision control program, and tell the computer to control the role of exercising control. 2, closed loop control system computer to the production of an object or process control, the state can directly influence the production process computer control system, called the closed-loop control system computer. Control of the computer monitor in the operator, the automatic acceptance of the production process state test results, calculate and determine the control scheme, the direct command and control units (devices) of action, the role of exercising control of the production process. In such systems, aircraft control components under control of control information sent to control device operation, the other running equipment condition as the output, measured by the detection part, the feedback as input to the control computer; to make control Computer \ Control Components \ production \ test components form a closed loop. We will call this form of control computer control closed-loop control. Closed loop control system computer, using a mathematical model to set the value of the production process and test results of the best value of the deviation between the feedback and control the production process to run at their best. 3, line control system as long as the computer controlled production of the controlled object or process, to exercise direct control, without human intervention are called the control computer on-line control, or on-line control system. 4, offline control system control computer does not directly participate in the control object or the controlled production process. It only managed to complete the process of the controlled object or the status of testing, and testing of data processing; and then develop control programs, the output control instruction, operator reference control instructions manually controlled operation to control parts of the object or subject control process control. This control form is called off-line computer control system. 5, real-time control system control computer real-time control system iscontrolled by the control of the object or process, or request when the request processing control, the control function in a timely manner to address and control systems, commonly used in the production process is interrupted for the occasion. Such as steel, each one refining furnace steel is a process; and if the process rolling, rolling out each piece of steel considered a process, each process is repeated. Only enter the process only requires a computer control. Once control of the computer, it requires a computer from the production process information in the required time to respond to or control. Such systems often use sophisticated interrupt system and interrupt handling procedures to achieve. In summary, an online system is not necessarily a real-time system. But a real-time system must be an online system.Second, in order to participate in the control mode to Category 1, direct digital control system by the control computer to replace conventional analog instruments and direct regulation to control the production process, as the computer as digital signals, so named after the DDC control. Actually controlled the production process control components, control signals received by the process controller input / output channels of D / (D / A) converter output of the digital control computer volume to be converted into analog; analog input control machine to go through the process of input / output channels of analog / digital (A / D) converter into a digital number into the computer. DDC control systems often use a small computer or microprocessor, the time-sharing system to achieve multiple points of control. Is in fact a discrete sampling with the controller, to achieve discrete multi-point control. DDC computer control system that has become the main control computer control system forms. DDC control of the advantage of flexibility, large, focused on high reliability and low cost. Can use several forms of digital computing circuits, or even dozens of loop production process, integral to proportional --- --- differential (PID) control to maintain the industrial state of the controlled object at a given value, the deviation small and stable. And as long as the change of control algorithms and applications can achieve more complex control. Such as feedforward control and the best control. Under normal circumstances, DDC-level control often more complex as the implementation of advanced control level. 2, supervisory computer control system supervisory computer control system for a particular production process, according to the production process of various states, according to the production process of the mathematical model to calculate the best production equipment should be running a given value, and the best value automatically or manually on the DDCExecutive-level computer or analog meter to align the regulation or control of the target set. By a DDC or adjust the instrument at various points on the production process (running equipment) to exercise control. SCC system is that it can guarantee the production process is always controlled the situation in the best condition to run, so get the most benefit. SCC results directly affect the merits of the first of its mathematical model, this should always improve the operation process model, and modify the control algorithm, and application control procedures. 3, multi-level control systems in modern manufacturing enterprises in the production process not only the need to address the problem of online control, and Huan Zhi Li called for a solution of production problems, the daily product line, the number of arrangements for planning and scheduling, and Rose plans develop a long term planning, notice Xiaoshou prospects, there was multi-level control system. DDC class is mainly used for direct control of the production process, for PID, or feedforward control; SCC level is mainly used for optimal control or adaptive control or learning control calculation, and command and control the same DDC class report back to the MIS class. DDC level usually microcomputers, SCC-level general use of small computers or high-end microcomputers. MIS Workshop main function of governance is based on plant-level production of varieties issued, the number of orders and collect up the production process of the state of information, at any time reasonable schedule to achieve optimal control, command and SCC-level supervisory control. Factory management level MIS main function is to accept the company and factory production tasks assigned by the actual situation of optimized computing, Zhi Ding factory production plans and short-term (ten days or weeks or days) arrangements, and then issued to the plant-level production tasks. Corporate governance level MIS main function is to guess the market demand computing to develop strategic long-term development planning, and contract orders, raw material supply situation and the production conditions, comparison of the optimal production program selection and calculation, work out the entire company business a long time (months or ten days) of the production plan, sales plan, assigned to the task of the factory management level. MIS-level main function is to achieve real-time information processing, decision-makers at all levels to provide useful information, make on the production planning \ scheduling and management programs to plan the coordination and management control in the optimal state. This one can control the size and scope of enterprise size divided into several levels. Each level has to be addressed accordingto the size of the amount of information to determine the type of computer used. MIS generally use small computer shop class or high-grade micro-computer, the factory management level of the MIS with a medium-sized computer, and corporate governance level MIS is to use large-scale computer, or use super computer. 4, distributed control or distributed control system distributed control or distributed control, the control system is divided into a number of independent local control subsystems to complete the controlled production process control task. Since the emergence of micro-computers and rapid development of distributed control to provide for the realization of the material and technical basis, in recent years, decentralized control can be different almost normal development, and has become an important trend in the development of computer control. Since the 70's, appeared focused on distributed control system, called DCS. It is a decentralized local control of the new computer control system.Three, classified according to the law regulating 1, program control if the computer control system the division of a predetermined time function control, such control is called program control. Such as the furnace temperature-time curves Anzhao some control on the process control. Here the procedure is time-varying changes have to determine the corresponding value, rather than the computer running. 2, sequence control in the process control based on the generated sequence control, computer, over time, as can be determined according to the corresponding control value and previous results at the moment both to exercise on the production process control system, called the order of the computer control . 3, proportional - integral - differential analog PID control regulation of conventional PID control instrument can be completed. Micro-computer can also be achieved with PID control. 4, feedforward control is usually the feedback control system, have certain effects on the interference in order to generate feedback over the role of inhibitory control of interference, and thus delay the control of undesirable consequences. In order to overcome the negative lag control, with the computer accepts the interference signal after the, did not produce effects in the Huan insert a feedforward control Zuoyong, it Ganghao interference point in the interference of the control to completely offset the effect on the variable, it was Ming Wei Yin Er disturbance compensation control. 5, optimal control (optimal control) system control computer, such as to have controlled object is best known as the best run of the control system control system. Such as computer control system is limited in the existing conditions, select appropriate control law(mathematical model), the controlled object indicators in optimal running condition. Such as the largest output, consumption of the largest, highest quality standards, such as the least scrap rate. Best is determined by a set of mathematical models, sometimes several in a limited range of the best indicators of the pursuit of individual, sometimes the best indicators of comprehensive requirements. 6, the adaptive control system, optimal control, when the working conditions or qualifications change, we can not get the best control effects. If the situation changes in working conditions, the control system can still be controlled in the best state of the object's control, such control system called the adaptive system. This requires mathematical model reflects the change in the conditions, how to achieve the best state. Control computer to detect changes in terms of the information given by the laws of mathematical models to calculate, to change the control variables, the controlled objects still in the best condition. 7, self-learning control system if the computer can keep the results under the controlled object gain experience running their own change and improve the control law so that more and better control effect, this control system is called self-learning control system. Above mentioned optimal control, adaptive control and self-learning control are related to multi-parameter, multi-variable complex control systems, are all problems of modern control theory. Determine the stability of the system, many factors affect the control of complex mathematical models, have to be a production control, production technology, automation, instrumentation, programming, computer hardware, each with various personnel to be realized. Controlled object by the length of reaction time required to control the number of points and mathematical models to determine the complexity of the computer use scale. Generally speaking, a strong need to functionality (speed and computing power) of the computer can be achieved. The Zhuzhong control, can be a single type also is not single, you can combine several forms to achieve control of the production process. This should address the actual situation of the controlled object, the system analysis, system design determined at the time.Keywords ：open the control,closed loop control。
