I want to ask about the basic knowledge and advantages of plc.

The full name of PLC is programmable logic controller (PLC), which is used to replace relays to perform sequential control functions such as logic judgment, timing and counting. The basic design idea of PLC is to combine the advantages of perfect computer function, flexibility and universality with the advantages of simple and understandable relay control system, convenient operation and low price. The hardware of the controller is standard and universal. According to the actual application object, the control content is compiled into software and written into the user program memory of the controller. The controller is easy to connect with the controlled object. With the development of semiconductor technology, especially microprocessor and microcomputer technology, since the mid-1970s, microprocessor has been widely used as the central processing unit in PLC, and medium-scale, large-scale or even super-large-scale integrated circuits have been adopted for input and output modules and peripheral circuits. At this time, PLC is no longer a logical judgment function, but also has the functions of data processing, PID adjustment and data communication.