Design And Implementation Of High Precision Automatic System For Solution Preparation

Solution preparation is one of the most basic work in chemical analysis,medical and health laboratory.Although the chemical analysis,biological analysis and other disciplines is developing fast,the high precision automatic system for solution preparation develops slowly.Most sample treatment with high precision requirements are still by manual processing.In the light of some inherent imperfection causing manual solution preparation such as a waste of time,tedious job with low precision,developing an easy-operating and high precision automatic system for solution preparation to replace manual solution preparation becomes a potential trend.According to the research on solution preparation system in domestic and abroad,a new high precision automatic system for solution preparation that has the function of precise preparation,proportional dilution,equal distribution and further development is brought up.And it can automatically repeat the same process as needed.The solution preparation system adopts intelligent design,which has the advantages of simple operation,convenient liquid distribution and high liquid distribution precision.The system consists of seven parts: the master computer module,the communication module of the slave computer,the control module of the slave computer,the pipeline-switching module,the drive circuit of the pipeline-switching,the auto-sampling module and the drive circuit of the auto-sampling module.Among them,the slave control module,the pipeline-switching module and the auto-sampling module constitute the slave execution system,which is convenient for users to realize further development.The slave control module uses STM32F103 as core controller to perform auto-sampling control and pipeline-switching control.The slave communication module uses a control board combining CC2540 with STM32F103 to implement the function of wireless instruction receiving from the master mobile phone and sending control commands.The host computer module uses Android mobile phone to complete the settings of the function parameters and the display of the action process.The main work of this thesis are as follows:First,relevant literature are consulted and the theory and composition of solution preparation system are summarized.Meanwhile,the design scheme is formed and the piston pump,pipeline and switching valve are selected by using the dilution process as research object.Second,to achieve the purpose of precise preparation,proportional dilution,equal distribution and further development,the hardware circuit and software program has been designed to realize automatic solution preparation with high precision.Third,some testing experiments were carried out on the solution preparation system.The sampling precision,accuracy and rate of the system were tested by proportional dilution experiment.The stability of the system was tested by equal distribution experiment.The results of the experiments were performed with atomic absorption and mass spectral analysis.The results show that the system can fully meet the requirements of the conventional standard solution preparation,not only has accurate sample data,good repeatability,but also can save a lot of laboratory personnel working time and dosage of chemical reagents.