In the middle and late 1970s, the programmable controller entered the stage of practical development, and computer technology was fully introduced into the programmable controller, which made its function leap forward. Higher operation speed, ultra-small volume, more reliable industrial anti-interference design, analog operation, PID function and high cost performance have laid its position in modern industry.
In the early 1980s, programmable controllers were widely used in advanced industrial countries. There are more and more countries producing programmable controllers in the world, and the output is increasing. This indicates that the programmable controller has entered a mature stage.
From the 1980s to the mid-1990s, PLC developed the fastest, with an annual growth rate of 30~40%. During this period, the analog processing ability, digital computing ability, man-machine interface ability and network ability of PLC have been greatly improved, and PLC has gradually entered the field of process control, replacing DCS system, which is dominant in the field of process control, in some applications.
At the end of 20th century, the development of programmable controller is more suitable for the needs of modern industry. During this period, mainframes and subminiature computers have been developed, various special functional units have been born, and various man-machine interface units and communication units have been produced, making it easier to match industrial control equipment with programmable controllers.