Calculation setting method and engineering setting method. There are frequency characteristic method and track basis method for theoretical calculation and setting method; engineering setting method includes trial and error method, critical proportion method, experience method, response curve method, etc. The characteristics of engineering setting out method can be adjusted directly in the process control system without knowing the process of mathematical model first. Simple, simple and easy to master. This design mainly adopts the trial and error method to set the parameters. The specific process is as follows