Industrial controllers are used in many modern systems, such as the interface between DCS system and enterprise system, so that the production process can be reflected in the overall operation of the business. DCS system is commonly used in industrial control fields such as oil refining, sewage treatment plant, chemical plant and pharmaceutical plant. This paper focuses on introducing the basic structure and types of industrial controller system.
1. Distributed control system (DCS)
The industrial controller DCS adopts centralized monitoring to coordinate the local controller to execute the whole production process. Through the modular production system, DCS reduces the impact of a single fault on the whole system. In many modern systems, an interface is set between DCS system and enterprise system so that the production process can be reflected in the overall operation of the business.
2. Data acquisition and monitoring system (SCADA)
SCADA (supervisory control and data acquisition) system is used to control and manage geographically distributed assets, which are generally scattered in thousands of square kilometers. In the process of industrial production, central data acquisition and centralized control are very important for the operation of the whole system. SCADA system is usually used in similar water supply projects, sewage treatment systems and natural gas pipe networks. SCADA control center centrally monitors and controls the field node equipment in the remote communication network, including alarm information and process status data. The central control center relies on the information obtained from the remote site to generate automatic or process driven monitoring instructions and send them to the remote site, so as to realize the real-time control of the remote device. This kind of remote device is the field equipment in the industrial field. The operation of field equipment is similar to the opening / closing of valves and circuit breakers, sensor data acquisition, on-site environmental monitoring and alarm and other local operations.
3. Programmable logic controller (PLC) in industrial controller
PLC is a second-generation new industrial control device based on the traditional sequential controller and the introduction of microelectronics technology, computer technology, automatic control technology and communication technology. The International Electrotechnical Commission (IEC) has issued regulations on PLC: programmable controller is an electronic system with digital operation, which is designed for application in industrial environment. It adopts programmable memory, which is used to store instructions for performing logical and arithmetic operations, and control various types of machinery or production processes. The programmable controller and its related equipment shall be designed according to the principle of easy integration with the industrial control system and easy expansion of its functions. PLC is widely used in almost all industrial production processes. It is a key component in SCADA system or DCS control system.
On the problem of industrial controller, this paper focuses on the basic structure and types of industrial controller system. Different types of industrial controllers have different characteristics, so they should be selected according to the situation.