Data Acquisition System Of CCD Accurate Diametric Measurement Device

In machinery manufacturing, precise machining relies on the means of accurate measuring, especially the online measurement technique, and outer diameter online measurement of shaft parts is very common. CCD (charge-coupled device), is a new type of semiconductor device, which developed in the early 70s of last century. With the essential optical system and suitable timing driven pulses, optical image of the part in the spatial domain can convert to video signal in the time domain by the CCD, the peak of each discrete signal in the video signal corresponds to light intensity received by the photosensitive units, the timing of output signal corresponds to the order of photosensitive units'position. Because of this special function, CCD can be utilized for nocontact, accurate and automatic measurement of small shaft parts.1. A nonconductor accurate measurement system for the diameter of micro-sized part was designed based on linear CCD imaging measurement in this dissertation.2. According to the requirement of the timing driven pulses of CCD, field programmable gate array (FPGA) chip was utilized. The hardware description language VerilogHDL is used to program the timing driven pulses of CCD. And the program has been complied and simulated in Quartusâ…¡8.1, Modelsim SE6.0 development environment. Eventually, I obtain the timing driven pulses of CCD, whose frequency is 1M.3. Signal processing and data acquisition from the output image signal of CCD were accomplished in this dissertation. How to differential amplify and low-pass filter the output signal from CCD, how to convert the output signal using A/D converter and how to adopt the data using microcomputer and static RAM memory were expounded. Then send the data to PC through the microcomputer serial communication port. The hardware and software of the signal processing and data acquisition were accomplished in this dissertation.4. The experiment of CCD timing driven pulses and signal acquisition circuit showed that the timing driven pulses could meet the requirement of CCD, which could output reliable electrical signal. The data also could be obtained from the signal acquisition circuit.