| In the food industry, the refinement purification is an important process, in witch the evaporator is the key device. Related technology researchs and analysis on the evaporator’s safty, reliable and economical environmental control scheme is needed. In order to deal with the probelem acuracly, the on-site environment, process equipment etc, and reproduce the industrial process in the laboratory conditions shoud be close to the industry field conditons. This research is based on SMPT-1000 which is a new experiments evaporator device with advanced multi-function control training system. SMPT-1000 can simulate industrial boiler an the evaporator, which provides a dynamic simulation model that can truly reflect the actual process of industrial production and meet the industrial level precision and repeatability requirements as well.Advance multi-function control training system of SMPT-1000 is researched in this paper. The liquid level, flow, density, temperature and steam pressure are the main controled parameters, and these parameters have been analysed in detail. Different control schemes are designed according to each parameter’s different characteristics. The evaporator density, which is difficult to be measured precisely, and a soft measurement method is given to calculate the evaporator density. Evaporator temperature has characteristics of nonlinearity, large delay etc. So the traditional PID control and neural networks’ advantages are combined, a PID control algorithm based on BP neural network is designed.The temperature controller includes on-line learning and on-line computing. Through experiments, the evaporator temperature channel transf-function model is established. The control algorithm is simulated by the Matlab M file. It is simulated and compared with the traditional PID control effect. The experiment result shows that this control algorithm is better than the traditional PID controller. In the section 4, the PID control algorithm based on BP neural network is implemented with program langauge SCL.Based on the control process requirement, basic control system and driving sequence control system and safety strategy are designed. Based on the control system scheme, the software and hardware is configured by the Simatic PCS7. The evaporator’ control and monitor is completed by the Simatic PCS7.The evaporator parameters curves are obtained according to the real-time operation. According to the operation process, the driving sequence control system and safety system can run very well, and fulfill the control requirement. Based on the above working, the control strategy and plan is proved to be feasible. |
