Research On Opto-electric Acquisition System Of Laser Particle Size

With the development of modern science and technology,particles play an important role in various fields.There are demands for particle size and its distribution.Laser particle size analyzer has the advantage of high precision,good repeatability,wide measurement ranges.It plays an important role in the field of particle size measurement.Based on the Mie scattering theory,the scattering signal of the particle is studied.The structural parameters of the laser detector in the laser particle size analyzer are optimized.The I/V conversion circuit with 56-channel photoelectric detector and data acquisition circuit based on serial port transmission were developed.The main work is as follows:1.The particle size measurement methods were explained.The principle of scattering measurement of particle size and other information was studied.Based on the Mie scattering theory,the angular distribution of particle scattering and the principle of light energy distribution were analyzed.It is the theoretical foundation for the detector improving design.2.The main structure of the photoelectric detector was analyzed,and the working principle of the photoelectric detector was analyzed.Based on the combined spectrum measurement method,the combination structure of the photoelectric detector was determined.According to the processing technology of the silicon photoelectric detector and the particle scattering angle distribution,the detector structure parameters were determined and optimized.Then a photoelectric detector mask plate was designed,and the detector mask board was processed.3.A circuit hardware system was designed.The LMP7704 chip is used for I/V conversion of the 56-channel photoelectric detector,the ADS7953 works as multiplexer and A/D acquisition.This circuit hardware system achieves the optical current signal to the voltage conversion,analog conversion and serial communication.4.The program of microcontroller was written under KeiluVision4 development environment.And it achieved initialization,signal gating,the transmission and receiving A/D data,and the communication between the upper and lower machine.5.The designed circuit was debugged and tested,and the data was analyzed.