The Research And Development Of The Antibiotics Titer Measuring System Based On Turbidity Method

Along with the development of the social and economic,the impact of antibiotics is increasing on people's live and industrial production. Commonly, titer is used to be represented of dosage of antibiotics, which is a relative standard level in the measurement of the antibiotic quality. Therefore, antibiotics titer determination is an extremely important way on antibiotics research, production and application.Firstly, by looking over technical documentation and investigation, the author summarizes the development, sorts and features of antibiotics titer measuring system, and then presents the significance of the theme. The antibiotics titer measuring system based on turbidity method has the advantages of short time, high sensitivity, simple operation, less human factors, affordable, little maintenance, high-accuracy and high-precision results, which is introduction of new technology, high-level, standardized measuring system. Secondly, introduces the basic principle of the turbidity method, which is the theoretical basis of the antibiotics titer measuring system to be able to analyze and detect turbidity. Finally gives the general structure block diagram of the measurement and control system.This thesis developed an antibiotics titer measuring system based on turbidity method. Studies have completed the design and installation of the measurement system, including mechanical design, signal acquisition, temperature control device design and system control core design. Detailed introduces the signal acquisition principle and device. Finished the research and development of the antibiotics titer measuring system based on turbidity method, which is a system used computer and data acquisition card as control core, integrating optical, mechanical, electrical and computer.This thesis mainly discuss the hardware design of the antibiotics titer measuring system, including signal excitation circuit, preamplifier circuit, signal regulate circuit and digital circuit. Each element circuit is analyzed in detail. Discusses the two programs of preamplifier circuit. Through theoretical analysis, selects the optimal scheme. There are many prominent places in the circuit design: Using a shift register to expand the data acquisition card's DO ports, which is used as multi-channel measurement channels switch; in order to improve the consistency of the measurement channels, adjust the resistance of LED to make each LED work in the linear area; in order to improve the resolution, make the final output voltage amplifier four times and the biggest unsaturated value is elected by the software.Finally, analyzes the errors of influencing the overall system precision, mainly environment error, mechanical structure error and hardware error. And analyzes the experimental data. According to data processing theory, shows the accurate and reliable of the experimental data, reaching to the technical index requirements.