The main application field of PLC
1. Switching quantity logic control
Replace the traditional relay circuit, realize logic control, sequence control, can be used for single equipment control, can also be used for multi-machine group control and automatic pipeline. Such as injection molding machine, printing press, stapler machine, combination machine tools, grinding machine, packaging production line, electroplating line, etc.
2. Industrial process control
In the process of industrial production, there are some such as temperature, pressure, flow, liquid level and speed and other continuous changes of the amount (that is, the analog amount), PLC uses the corresponding A/D and D/A conversion module and a variety of control algorithms to deal with the analog amount, complete closed-loop control. PID adjustment is a kind of adjustment method used in general closed-loop control system. Process control is widely used in metallurgy, chemical industry, heat treatment, boiler control and so on.
