The fieldbus technology is the key technology of high-grade CNC system,due to the difference of agreement and architecture,different buses cannot communicate directly.For NC system which generally integrates with multiple bus equipment,in order to realize the control of the different bus protocol NC equipment,data transfer device between buses needs to be designed.This paper mainly aims at the requirement of data conversion for NC system which integrates with POWERLINK and NCUC-Bus,develops a connected device supporting NCUC host with POWERLINK from the two-way communication,which is used to the interconnection between two Bus.The complete implementation of the agreement of POWERLINK itself is the premise of POWERLINK with NCUC-Bus interconnection,based on the analysis of principle of POWERLINK,and on the basis of comparing POWERLINK universal implementation scheme,according to the requirements of industrial control field of communication performance,this paper chooses an implementation plan whose link layer function is realized by hardware description language and application layer is based on microprocessor implementation,on this basis,the overall architecture of the connected device is analyzed from the aspect of software,and the hardware platform of the device is designed.POWERLINK agreement includes physical layer,link layer and application layer,this paper firstly integrates hardware protocol stack of POWERLINK,and designed a interface between data link layer and application layer to match different data size and time series.In order to integrate with existing soft PLC development platform to achieve the purpose of application layer compatibility,this article does not adopt the CANopen of openPOWERLINK protocol stack provided by B&R,but develops the application layer based on CANfestival protocol stack from three aspects: the process data communication,the data communication and the object dictionary building,and designed a frame parsing program to parse POWERLINK data frames.On the basis of above studies,the NCUC-bus and POWERLINK interconnection schemes are analyzed.The connected device is designed from three key parts: NCUC master-slave communication module,interface and POWERLINK master communication module,which realizes two-way communication between NCUC master with POWERLINK slave.On the above research contents,this paper designs experiments to validate communications functions,synchronization and real-time of POWERLINK as well as the communication function between POWERLINK and NCUC – Bus.The experimental results show that the designed POWERLINK communicates normally,compared with the implementation scheme of software based on microprocessor and the scheme of soft core based on FPGA,the real-time capability has improved.NCUC master with POWERLINK slave has the capability of two-way communication,which proves the effectiveness of this method. |