Design And Implementation Of CCD Measurement System Based On CPLD

With the elevated speed and precision in the area of measurement, non-contact measurement is replacing traditional contact measurement in many fields due to its good accuracy, real-time and no damage. As a semiconductor device that use single charge as its sensor signal, Liner CCD can easily achieve very high accuracy under suitable drive circuit, and it is used widely in the area of monitoring, examination and measurement.In this thesis, based on direct light of Laser Triangulation Measuring principle, a non-contact measurement system with high precision and wide range is designed, which is mainly controlled by Single Chip Micro-computer. It uses the programmable logic device (CPLD) to realize the CCD drive circuit. The transducer's laser source is semiconductor laser diode.Firstly, research is carried out in current study situation both at home and abroad, and Laser Triangulation Measuring principle is described. Secondly, the working principle and chief properties of Liner CCD are analyzed. Thirdly, the hardware structure and software design of the system is introduced in detail. The optical signals are converted to electric signals by laser-CCD sensors, then sent to Single Chip Micro-computer for A/D transform before amplifying and filtering, the acquired data will be transmitted to the upper computer by the serial communication of RS-232C for further processing. Lastly, System Adjustment and experiment process were demonstrated, analysis is made on the experimental results and errors, and some opinions for further improvement of performances of the system were given.In this paper, CCD timing pulses of Laser Triangulation Measuring System was generated by using CPLD as the control core, and it's integral time is adjustable as required. This not only increased the reliability and flexibility of the circuit, but also reduced the size of the hardware apparatus. In addition, taking MCS-51 single chip as processor is very simple, the cost is also reduced. The measurement system has a very good application prospect among non-contact measurement area, with its precision as high as 0.1mm and measure range of 20cm in theory.