Abstract : This paper proposes a dual-CPU open CNC system with a PMAC motion controller as the core of the control system and an industrial control computer as the system support unit. The system's functions, hardware, and software design methods are introduced. Practical application demonstrates that the PMAC-based CNC system can fully realize the customization of the human-machine interface and the parameterization of real-time control components. Keywords : PMAC, Dual CPU, CNC system, Panel milling machine This paper proposes a dual CPU CNC system with a DMAC (programmable multiple axes controller) multi-axis motion controller as the CNC module and an industrial control computer as the system support unit. It achieves two levels of openness: customization and parameterization of the human-machine interface and non-real-time control components; and parameterization of real-time control components. 1. Hardware Structure of the CNC System 1.1 PMAC Multi-Axis Motion Controller The PMAC multi-axis motion controller is a product of Deha Tau Corporation in the United States. It is a high-performance servo motion controller. Utilizing Motorola's DSP5600/56002 digital signal processor, it can simultaneously control 1-8 axes. It can execute programs stored internally, motion programs, and PLC programs independently, and can perform servo loop updates and communicate with the host computer via serial port and bus. PMAC can also automatically determine task priorities, thus enabling real-time multi-tasking. This function greatly reduces the burden on the host computer and programmer in terms of processing time and task switching, improving the overall operating speed and control accuracy of the control system. 1.2 CNC System Hardware Structure and Working Principle The control center of this CNC system is based on an industrial PC (IPC) platform, employing a PMAC multi-axis motion controller and dual-port RAM (DPRAM). The CPU on the IPC and the CPU (DSP56001) of the DMAC form a master-slave dual-microprocessor structure. The PMAC mainly handles the motion of the three axes of the machine tool and the control of the control panel switches, while the IPC mainly implements the system management functions. To realize the PMAC multi-axis motion control function, corresponding I/O boards, servo drive units, servo motors, encoders, etc., need to be expanded on the PMAC board, ultimately forming a complete CNC system. Its structural principle is shown in Figure 1. [b][align=center]For more details, please click: PMAC-based Parallel Dual-CPU Open CNC System[/align][/b]