Research On Soft PLC Of Machine Tools Embedded CNC System

Since the advent of PLC technology, PLC has its high reliability, strong anti-interference ability, dedicated and modular design for harsh control of the scene, etc., in the field of industrial control and other industries are widely used, but the soft PLC hardware design closure is becoming the main reason for limiting its further development. PC-based soft PLC platform with its open software and hardware architecture and other advantages, to obtain a more rapid development, but due to lack of PC-based soft PLC platform in real-time as well as cost control, as well as the rapid development of embedded systems embedded soft PLC emerged, only to realize embedded soft PLC functions PC based soft PLC platform, while in real-time, cropping systems, resource allocation and cost control have a strong competitive advantage.Embedded CNC system is the rapid development of this research direction, the system includes a man-machine interface and the motion controller, and other auxiliary functions such as hydraulic lubrication from a PLC to complete, so the machine does not control all the functions in the embedded to the machine device. Based on the numerical control system based on human-machine interface for embedded u C/OS-II on the proposed new soft PLC in CNC machine tools for embedded system functions, auxiliary machine control functions will be embedded into the device to the machine. In this paper, CNC machine interface to the host controller hardware platform ARM9 core module for the system, its external expansion interfaces such as storage devices and systems, such as LCD screen, CNC keyboard, UART, I/O interface board and other external devices. Choose between the main control board and I/O interface board real-time bus RS422 communication protocol.Mainly on soft PLC completed the following tasks: uc GUI based graphics support systems, design software and soft PLC PLC editing interface running interface, interactive editing to achieve functional modules. Depth-first traversal algorithm, the ladder logic into a tree, to achieve ladder program is compiled to run programs designed for soft PLC input sample ladder program execution, the output refresh the three parts, plus data exchange interface design, realization compile module functions. Underlying driver module consists of LCD display drivers, key programs and I/O interface board communication program implementation.