Design And Implementation Of PROFINET Servo Slave Interface Based On ERTEC200P

PROFINET is a new generation of automation bus standard based on industrial Ethernet technology introduced by Siemens and PROFIBUS international organization.And it is suitable for a variety of industrial control fields.Meanwhile,it has a broad application market in China.However,the current domestic servo products with PROFINET are few.And the real-time performance is poor.They are not beneficial to the improvement of domestic servo brand competitiveness.Therefore,an implementation scheme of PROFINET servo slave interface based on ERTEC200 P is proposed.Based on the analysis of the structure of the PROFINET communication system slave station,the functional requirements of servo slave station are obtained.By using the dedicated communication resources in ERTEC200 P and the mature servo control algorithm of the research group,the hardware structure and software architecture of the PROFINET servo slave interface are designed,which combined with STM32F407.Based on the characteristics of PROFINET slave station link layer for data transmission through slots and subslots,the e COS real-time operating system is used.And a priority preemptive scheduling algorithm is introduced.Furthermore,by using the underlying function interface of ERTEC200 P,the thread switching and processing flow of the three communication tasks at the link layer are designed.At last,the communication task modules are verified by online simulation.By studying the structure of profiddrive common axis object,shared memory is used as the transmission medium.Combined with polling handshake and interrupt timing design,the link data transmission APIs of the application layer are designed.And the high interchangeability of the PROFINET slave application layer is realized.Based on these APIs,the universal speed state machine,position sensor state machine and fault buffer conforming to the PROFIdrive specification are realized.Furthermore,the Bitmap mapping algorithm is used to improve the stability of fault information uploading.Finally,Real-time power state switching control,position control and fault response are realized.In PROFINET speed mode,there is a problem of long update cycle of control commands.Therefore,based on AC4 application class,the dynamic servo control function is introduced.Combined with the central interpolation algorithm of the communication master station,the position loop interpolation calculation is performed with the servo control cycle.Meanwhile,the closed-loop position control mode of the servo is realized.And the control stiffness of the bus system is improved.A systematic experimental platform is built to test the interface function,such as cycle communication,uncycle parameter read-write communication,fault diagnosis and motion control.Performance tests such as compatibility,stability and synchronization are also carried out.The experimental results show that the interface completely realizes the communication function and motion control function required by the servo driver.Moreover,it is compatible with common PROFINET master and slave devices.And the synchronization jitter is only ±13ns.And the operation is stable.They prove the feasibility and excellent performance of the PROFINET servo slave interface solution.