Longfeng Automation Training Center, program-controlled education, Shenzhen Control PLC Training Center, Bafanghui, Fuchuan Engineer College, Ji Cheng Training Network, University of Electronic Science and Technology of China Vocational Skills Training School, Changsha Lake Xiang Vocational and Technical Training College, Cixi Hangzhou Bay Secondary Vocational School, Zhengzhou Zhengding Automation Technology Co., Ltd. ..

A, programmable logic controller

Programmable logic controller (PLC) is a digital operation electronic system specially designed for industrial environment applications. It uses programmable memory, which stores instructions for logical operation, sequence control, timing, counting and arithmetic operation, and controls various types of mechanical equipment or production processes through digital or analog input and output.

Second, the working principle

When the programmable logic controller is put into operation, its working process is generally divided into three stages, namely, input sampling, user program execution and output refresh. The completion of the above three stages is called a scanning cycle. In the whole operation process, the CPU of the programmable logic controller repeatedly executes the above three stages at a certain scanning speed.

Third, the selection rules

In the design of PLC system, the control scheme must be determined first, and then the selection of PLC engineering design. The characteristics and application requirements of process flow are the main basis for design and selection.