Development Of Interface Card For Grating Sensor Based On Ethernet

Grating sensor is an important device for precision measuring, which is widely applied in the fields of position measuring, numerical control machine, automation control and so on. With the fast development of network technology, existing subsequent electronic devices for grating sensor become difficult to meet the need of the instruments internetizing. In this thesis, an interface card which can process the signal of grating sensor and access Ethernet is developed.Firstly, the network foundation which is necessary in designing an Ethernet interface circuit is introduced. It includes technology characteristics of Ethernet, the protocol model and the process of encapsulation and demultiplexing of TCP/IP. Besides, four schemes for realizing embedded Ethernet are discussed.Secondly, the methods of designing the interface card for grating sensor are illuminated. In the part of hardware design, the grating signal processing module is designed in a CPLD device. The methods of realizing the functions of filtering, four-subdivision, sensing, counting and MCU interface are described in detail. The internal structure and principle of Ethernet controller are analyzed, and the Ethernet interface circuit is designed using this controller. In the part of software design, the initialization of Ethernet controller and the process in which Ethernet packets are received and sent are studied thoroughly. After analyzing the embedded TCP/IP protocols, the interface card software which can control the whole card, receive and send Ethernet packets is completed.Lastly, the concept of windows network application based on Winsock is presented. The testing software for grating sensor is developed. In addition, the experiments that measured signals from grating sensor are given. The experiments results prove that the interface card can work perfectly.