Research And Design Of Automatic Control System Of Powder Injection Preparation

A series of physical and chemical processes needed to be carried out to produce thepowder injection preparation. By analyzing the demand and process of produce, andcombined with Chinese GMP revised in2010, two key technical difficulties were discovered:the temperature control when sterilizing and the evaporation tank’s pressure control and thenitrogen’s flow control when rotating and evaporating.The method of temperature control when sterilizing was studied. All the temperature ofthe monitoring sites should be controlled in121~127℃when sterilizing. In consideration ofthe admission mode of pure steam, the work characteristics of steam trap and the layout ofpipes of the whole system, all the temperatures fluctuated frequently. By means of calculatingthe value ofF0and adjusting the sequence and time of steam admission, all the temperatureswere controlled effectively and the sterilizing process went on smoothly and the processrequirements and Chinese GMP revised in2010were satisfied.The algorithm of evaporation tank’s vacuum degree control and the nitrogen’s flowcontrol were studied. In the rotating and evaporating process, the two procedures that vacuumthe evaporation tanks and fill nitrogen into the tanks at the same time would act and reactupon one another and the temperature was always changing. It became difficult to make thesystem steady and meet the process requirements with traditional PID. Through expert PIDalgorithm and the compensation of temperature and pressure for the nitrogen’s flow, thebalance of the two procedures was effectively controlled, and the control of system stabilitywas improved.The automatic control system of liquor preparation was designed based on S7300PLC,including hardware design and software design. The two key technical difficulties’ controlalgorithms were verified by the experiment. The result indicated that the temperature controlwhen sterilizing and the evaporation tank’s vacuum degree control and the nitrogen flowcontrol when rotating and evaporating satisfied the process requirement and achieved a goodeffect which supported the enterprise’s production.