Research And Development On Position Control Card In Open Numerical Control System Based On DSP

Position control card is an important component of the open CNC System; it is responsible for controlling the exact positioning of each axis and plays a decisive role in machining accuracy. The position control card which adopted modern means such as DSP controllers, FPGA/CPLD, general-purpose computer has become the mainstream of the development direction in current. It has features of strong information processing ability, and high open degree, convenient position control and good general characteristics. First of all, the article analyzes the important role of the numerical control technology in modern manufacturing and the status of CNC system and position control at home and abroad.On this base, the article put forward the entire hardware design project: developed a"PC+NC"position control board based on the motor control chip TMS320LF2407A DSP produced by American TI company and new CPLD chip MAX II EPM570 produced by Altera. Position control card which uses DSP as nuclear processor,can achieve complicated control algorithm expediently, improve control performance and synchronously integrates quadruple frequency and phase discrimination count circuit into CPLD which simplify the design methods of digital circuits. At the same time, the article discuss the control card's various function modules in detail such as DSP minimum system, DSP peripheral circuits, D/A converter circuits and position detection circuits based CPLD. In this paper, the software of the control system which includes the main program, interrupt service routine, D/A conversion function and PID control algorithm is be introduced briefly. Finally, we debug the DSP minimum system module, CPLD module, DSP peripheral circuits'module in hardware and software; verify the design of position control card of the validity and reasonable.