Development Of Network Node With High Speed I/OBased On Embedded PLC

The development of the Network Control System improved the application of the embedded PLC that contains CAN communication protocol in the field of industrial control. The technology in the motion control field is the key technology that impels new technologic and industrial revolution. The small and medium type of PLC with the function of high speed I/O takes important part in some motion control systems. With the development of the micro-electronics technology, the electronic measurement technology and the control technology, the high speed pulse signal is needed to be processed in more and more application situation. High speed pulse output of the small and medium type of PLC has a wide application in some aspects, such as the orientation control, in the motion control system. Most of PLC offer the function (or module) of high speed pulse signal processing and of high speed pulse output.In the thesis, the hardware structure of embedded PLC based on the C8051F040 MCU, the basic function and the structure frame of the embedded PLC kernel are presented. The development system of the embedded PLC software platform is introduced briefly, and the method of developing network node based on the embedded PLC's CMOS chip group is given.On the basis of studying the function characteristics and the operating principle of high speed I/O of other PLC, considering the situation of the software and hardware platform of the embedded PLC, a high speed I/O network node is developed. From the application view of users, the thesis presents a whole design of high speed counter of the node. In the process of designing pulse frequency measurement, firstly, two basic methods of the digital frequency measurement are presented, and then the advantages and the disadvantages of each method are given. The network node is designed to offer 4-channels high speed pulse output, and each channel can be controlled individually. During the realization of the high speed I/O of the network node, Programmable Counter Array (PCA0) provided by the C8051F040 MCU of the hardware platform of the embedded PLC is used flexibly. At last, the thesis gives some tests which testified the performance of the node, and then an application of the node in the pipe bender system is introduced in details.