Based On PCS7 Citricacid Purification Control Algorithm And Optimization

Citric acid is an important food additive in food processing industry, also widely used in pharmaceutical, chemical and other industries. The purity of citric acid is often short of asks by fermentation and extracted, so citric acid need further purification on this basis. The traditional processes of citric acid purification are backward, and automation degree is not high, so it will waste a lot of manpower and material resources and serious influence the efficiency of enterprises. Germany Siemens SIMATIC PCS7 is an industrial control platform, which is based on the thought of a complete automated process control system. By using Siemens PCS7 in citric acid purification production line, the entire system will be automatic, which has good compatibility and strong stability. The monitoring software HMI is WinCC in PCS7. According to the request, it can realize the function, such as back up the compression data, inquire history curve analyst, the voice alarm, inquire alarms etc.In the modern industrial control field, PID controller is widely used in single loop adjustment system, which controls temperature, pressure and flow rate. The control effect of PID controller is directly related to the value of the three parameters. In the industrial process most of the control object are high order, time delay, nonlinear, so the PID controller parameter optimization is more difficult. At present some advanced control theory has been introduced to process control, PSO-PID is one of them. PSO algorithm due to its simple, the program is easy to realize, the parameters need to adjust less, so it has been widely applied in scientific computing and engineering application fields and showed good application effect.This paper first analyzes the citric acid purification process and the characteristics of Siemens PCS7 process control system and the programming language, and it expounds the characteristics of the configuration software WinCC in PCS7 and its design principles. FM355C module corresponding to the PID controller is analyzed. Combined with the actual process control requirements, design the whole control system hardware configuration, software configuration and PC interfaces for subsystems. At last we propose using particle swarm algorithm to optimize PID parameters. By MATLAB simulation, the simulation results show that the algorithm is easy operation, fast convergence rate, high precision optimization and not easy to fall into local optima value, etc. The entire system is put into operation in June, 2010, and the system runs stably, archives the design goal.