The Study Of Photoelectric Sorter Data Acquisition System

Sorting is a way to sort and remove infested objects by using photoelectrical technology. The most important part of sorting is accurate data acquisition of the materials. CCD (Charge Coupled Devices) is a sensor integrated the optics to electronics conversion, charge storage and charge transition, which is applied widely in some fields such as camera and industry measurement and so on recently as its feathers of self-scanning, high aspect ratio, high sensitivity, compact structure and accurate pitch position etc.The thesis mainly studies the data acquisition system of photoelectric sorter. The system uses XC3S50 FPGA by Xilinx as the core controller and processor, and uses linear CCD sensor to scan the grainy materials and acquire the image data. The image data through the image digitizer which included the image signal conditioning, A/D converter is cached by the external memory and processed by the data process module. The system can realize the display of data acquisition waveform real-time on PC.At the beginning, the thesis detailed introduces the CCD working principle. Then the designs and implementations of the drive circuit of CCD camera; the image signal conditioning, sample and store circuit; communication circuit for data transmit; power supply circuit for the voltages and EPP interface circuit are introduced in modules. Based on FPGA technology, the system realizes CCD time sequence logical control, CCD image data sample and store. Besides, the design completes synchronous serial communication system based on self-defining protocol; furthermore, the design completes the sample image data acquisition and transmission. Upper computer writes the data acquisition application programs with VC++ and realizes the waveforms of data real-time display. The hardware circuit is mainly designed based on high-speed LSI (Large Scale Integrated) circuits and multi-layer circuits. Because of this, the design has high reliability and the size of the PCB (Printed-Circuit Board) is small and matches the camera lenses and volume.In this paper, the hardware description is realized in Verilog language. Using Xilinx ISE software has completed the simulation, synthesis, implementation and configuration. The experimental results prove the stable output of CCD and operation of data acquisition system are achieved, test waves are given out. The system's performance and next study directions are summarized which can provide some experience for further research.