Design And Implementation Of Communication Platform Based On Loongson CPU In CNC System

The communication platform of CNC system is the basis of information interoperability among function modules and field equipments. The development of open CNC and network CNC and the improvement of high-end CNC put forward higher demands to it, especially in realtime and non-realtime inter-module data exchange. Directed to the needs of CNC in the National Science and Technology Major Project, this dissertation focuses on the research of communication platform and key technologies in Lantian NC-200 based on Loongson CPU.The communication platform of NC-200 is Realtime Control System(RCS), which uses shared memory to realize inter-module data interaction in single processor. But shared memory doesn't fit all kinds of data exchange. In addition, the software- hardware design is dense and the computation and communication loads are heavy, which is unfavorable to functional extension.In order to solve above problems, the main contributions of dissertation are summarized as follows:1. Design and implementation of inter-module hybrid interactive mode. In view of the limitation of shared memory in CNC, an efficient hybid model SF integrating FIFO and shared memory is presented. According to the features of modules, the communication scheme in CNC is redesigned. The experimental results verified the validity of the model and the rationality of the scheme.2. Design and implementation of network communication platform. To meet the demands of CNC, a network architecture is presented. A resource-consumption and low coupling module in CNC is disjoint first from other modules. RTnet is used for communication between remote modules. Linux Real Time mechanism (LXRT) is used to improve realtime performance of data process and data transmission in user space. A prototype system is developed based on the above design idea. The experimental results verified the feasibility of the scheme.