Arm9-based Wireless Grating Displacement Measuring Technology Research

Modern displacement measuring technology is increasingly seeking to automate, unattended, cluster control, low-power. The measuring data is transmitted more by wire in the traditional field of machine turning and Bridge Monitoring, The reasons of the complexity of equipment, constraint of space and the high cost of wiring restrict the use of measuring instruments. With the development of microelectronics and communication technology, short-range wireless communication technologies with its strong anti-interference ability, less restriction and flexible installation have a widely used in many fields. The introduction of wireless transmission technology in displacement measuring technology has important theoretical significance and broad prospect of application.In this dissertation, the transmission and processing of measuring data in displacement measuring techniques and the corresponding program are researched more. The measuring data of nodes is transmitted to data center by wireless transmission with TREE" topology to compute and analyze. Firstly, the theory of optical grating, which is used more in displacement measuring technology, is analyzed, and on this basis, the measuring signal processing module, additional function module and wireless module of measuring node are designed with PIC microprocessors, besides, corresponding programs of which are designed too. The "ARM-LINUX" platform is used in data center, and the ARM9microprocessor S3C2440A is used in hardware design of data center. A7102RF chip is used in wireless module of whole system, based on the analysis of important parameters and introduction of the network architecture and protocol of ZigBee, the architecture of wireless protocol is designed with "TREE" topology which has data center, router, measuring node, and using "hierarchical thinking", the structure of wireless transmission protocol include physical layer, data link layer and application layer, the data frame structure, address structure, control commands and workflow of data link layer are introduced more. The driver of the wireless transmission protocol is designed through the introduction of the theory of embedded LINUX kernel and driver. Verify the system design through the test case, the driver can assign address to the measurement nodes, and read the measuring data, and control the additional function of the measurement nodes. The wireless modules have strong interference ability, and the transmission distance is very far away.