A Fast Axial Flow CO₂ Laser Control System Based On DSP And Fieldbus Technology

With the constant expansion of industrial production scale, high-power CO₂ laser processing system has to monitor more and more variables and process more and more data. Real-time performance, higher precision and system integration level are also increasingly demanded. The paper analyses the shortcoming of the current laser control system and puts forward a new control system based on DSP and Fieldbus technology. The control system can simplify the hardware structure, improve the laser intelligence degree and reduce the difficulty and cost of wiring and maintenance. And it has broad prospects compared with the previous laser control system. The paper mainly studied the control device design based on DSP2407 and Fieldbus technology.Firstly, according to the design requirements, the overall design of the control system is carried out. And multi-power supply system is adopted, the laser control signals and fault information are also analysed in detail, the hardware structure of"DSP motherboard + interface board"is designed, and some hardware anti-interference measures are adopted such as photoelectric coupler, passive filter, over-voltage protection and four layers PCB and so on. The software self-diagnosis function is also designed to improve the system reliability and stability.Secondly, the hardware of the control system is designed in detail. TMS320LF2407 DSP chip is chosen as the key control chip, and CPLD of MAXII series is adopted to cover the interface shortage of DSP2407. System function modules are designed such as the smallest system of DSP2407, IO and chip control logic expansion, storage space expansion, CAN bus module, USB data storage module, Ethernet remote diagnosis module, digital signals input and output circuits, analog signals acquisition circuit, communication circuits and so on.Then, the fieldbus structures of the fast axial flow CO₂ laser are designed in detail. The structures and functions of intelligent control units, communication message format and software realization method are also studied.Finally, CPLD design and simulation are carried out by QuartusII. DSP program design is carried out by CCS3.1, such as the laser automatic control flow, AD sampling and filtering programs, communication program with supervisory computer. The control system is debugged by using simulation laser signals, and it can achieve control requirements.