Study Of The Embedded System In Multi-channel DNA Analyzer

Over the last twenty years, molecular genetics has made remarkable achievements. These are contributed by the development of analytical technologies and analytical instruments. DNA analyzer, as the basic instrument of molecular genetics is also made a considerable progress. We do hold up quite well in the field of DNA analysis technology and its applications, but unfortunately there is no DNA analyzer which is with completely independent intellectual property rights can be found in the market.This topic is supported the Ministry of Science and Technology Innovative Method of 2008, which aims to develop high-throughput, high efficiency and on-site performance DNA analyzer. High-speed DNA sequencing and fragment sizing are achieved through electrophoresis and capillary array electrophoresis has been employed to enhance the throughput of the novel DNA analyzer. Confocal laser induced fluorescence detection (LIFD) system is adopted because of its high sensitive and high signal-to-noise ration. Optical scanner consisted of f-theta lens and galvanometer is used to detect multi-channel DNA samples. Only one PMT is sufficient to detect different fluorescence signals by using one time-sharing color filter wheel. Embedded system is designed to minimize our system and provide stable and reliable control.This thesis studies the embedded control system applied to novel multi-channel DNA analyzer. By analyzing the control requirements of the novel DNA analyzer, evaluating different designs to choose the final design schemes those meet the control needs and are also cost effective. The embedded system adopts LPC2378 as the main controller which is an ARM7TDMI-S based high-performance 32-bits RISC microcontroller, and other control circuits are extended for auto gel filling, auto sampling, high voltage control, optical scanner, weak fluorescence data acquisition et al, to implement fully automated DNA analysis. The frequency of optical scanner has been set to 8Hz. The maximum sampling rate of data acquisition system is up to 63kpbs, while its limit of detection is 5LSB and dynamic range is up to 13 bit.Meantime the effect of defocus of the galvanometer on fluorescence collecting efficiency was analyzed through theoretical analysis and optical simulation. The Fluorescence Collecting Efficiency Non-Uniformity (FCENU) was defined to evaluate the inconsistency of fluorescence collecting efficiency in whole view field. Simulation results show that FCENU of the 48-channel LIFD system is 6.92%. At the end, we built an experiment platform with LIFD system and the homemade embedded control system to verify theoretical analysis. Experimentalresults demonstrate that FCENU of actual LIFD system is 7.61%, larger than simulation results.