Studying On PH Control Method And Design Of The Controller

The process of pH control is applied in many industries including petroleum, chemical industry, medicine making, paper making, waste water treatment and water supply. It is very important to make the pH value in a certain range, or else it may debase the quality, waste the material, block the production and bring the pollution. Therefore, pH control is significant.Firstly, the mechanism model of the pH control and the actual control are analyzed, and the static model and the dynamic model are established. On the basis, the pH characteristic curve is got. Secondly, according to non-linear characteristics of pH value's process, fold lines are used to simulate non-linear curves. Based on advanced PID control algorithm, a kind of variable gain PID control algorithm of separate-segment is designed to compensate for non-linear characteristics of pH value's process. pH value's control process is simulated by using Matlab, and the general PID control algorithm is compared with it. It is turned out that the designed method can solve the non-linear problem of pH value's process, and that the control effect is satisfactory. Therefore, optimized control is realized. At last, a controller of pH value is designed based on the MCU of AT89S51. Software and hardware are designed, and the controller realizes some functions such as data collection, data processing, data display, keyboard scanning and so on.By testing the controller, the feasibility is validated. And the designed algorithm is helpful to promote the development of pH value's control system.