Development Of Distributed Control System For Polysilicon Manufacturing Based On SIMATIC PCS7

As a kind of clean and reproducible energy,the development of the solar battery has gained more and more attachment.The demand of the polysilicon,which is the main resource of solar battery,is increasing rapidly.But the conflict between the demand and the supply of the polysilicon is serious because of the low efficiency of the polysilicon manufacturing control system.In China the lack of the supply is a big problem and the key solution to solve the problem is that the related control system should be updated and improved.The controlling of the polysilicon manufacturing belongs to the continuous controlling category,the process not only has to deal with large numbers of process variables but also need complicated controlling logic according to the processing technique.In addition,the mixture ratio and transmission of some harmonious resource made the manufacturing be a process of high risk,so the control system should be has highly stability in process running.The thesis introduced a new DCS system for polysilicon manufacturing based on the SIMATIC PCS7,aiming to prompt the production efficiency,the newly developed system have the improvement compared with the traditional design:1.To avoid the risk caused by the shutdown of the system,the system use redundancy dispose in the hardware integration.From the redundant OS server and CPU with time synchronization,to the redundant circuit module used in I/O interface,the overall redundancy from HMI to automation station has ensured the high standard of fault-tolerance and system running stably;2.As the polysilicon manufacturing belongs to highly continuous processing controlling category,the thesis introduced a new controlling method of device integration(including actuator and transmitter),which is newly developed and first used in the controlling of the polysilicon manufacturing.The system used the Equipment Module(EM) to deal with specific functionality instead of the individual device controlling,however the EM is composed of the site devices which achieve the functionality such as material discharge etc;3.Newly designed and developed the panel access communication functionality between tank farm area and production plant area.The system operate excel resource database to set and inquire the material charge in request through the next steps: creating of specific data structure->VBS inquiring script->building of interface module(send and receive module) in Continuous Function Chart(CFC) ->Establishment of communication between the automation station(AS).The communication functionality is designed for the charge in EM and discharge EM when there occurs a material supply request from plant area.After the site performance of the newly developed DCS system,the redundancy dispose has ensured the higher running stability than that without redundant hardware,the system may stay running by using the spare CPU and Profibus-DP bus connection when in maintenance;with the new EM controlling method,the system has accumulated to a higher class of controlling continuous with no time delay;at the same time,the panel access system for material transmission between the tank farm and production plant has played an important role to improve the order and accuracy of the whole control system.The real site performance data shows that after using the new developed DCS system,the output of the polysilicon annually has gained 100%increase than that of last year as well as the 40%decrease of the costs in maintenance,which help a lot in improvement of the product efficiency.