Open Cnc System Based Digital Acquisition Technology

Digitizing collection is one of the key technologies of the reverse engineering. Nowadays, most of the Digitizing & Copying systems are based on DOS and single CPU. Those systems are of many disadvantages, such as poor flexibility, long period of developing, unfriendly manipulate interfaces and high price. Therefore the digitizing collection technology based on open CNC system is studied in this paper.Double CPUs architecture is used in this system. The host computer is Advantech IPC. The slave computer is PMAC. DPRAM, servo motors, A/D conversion board, 3D analogue probe, I/O board are chosen in this system.Most of the real-time tasks are controlled by PMAC, such as scanning, interpolation, position control, acceleration and deceleration, input & output, writing the sampled points to the DPRAM and so on.The background management, such as initialization, adjusting of parameter, display of motor position etc., are completed by the host computer through the functions of PMAC DLL PComm32, which is provided by Delta Tau Data System INC. Multithread multimedia timer and double buffer are used to read data from DPRAM. It solves the problems of real-time data gathering and huge amount of the sampled points storing.During this research, lots of experiments have been made in practice. Sampled points on different kinds of cured surface are gathered successfully. The feasibility of this project has been fully proved.