Development Of A New Type Data Processing System For Photoelectric Encoder

Photoelectric encoder widely used in CNC machine, robotics, radar, Photoelectric theodolite, military, aerospace and other fields, is an ideal sensor for automation equipment. With the development of industrial control in our country, interface technology of Photoelectric encoder for the acquisition and transmission has made great progress. How to the Photoelectric encoder connected to the industrial control bus and achieve data collection and delivery has become important issue to be study and solved. The output data of traditional Photoelectric encoder is the original single-ended or differential signals which only represents the encoder disk signals, It is not conducive to monitoring and testing of fieldbus and not suited to the requirements of industrial control, common bus type Photoelectric encoder overcome the above disadvantages, it has become an intelligent node in industrial fieldbus. Sending the appropriate message to achieve Photoelectric encoder serial data transmission, it will meet the requirements of industrial control.In order to meet the requirement of the data collection and transmission, using dsPIC30F4011digital signal controllers, which is produced by Microchip Technology Inc, as the Photoelectric encoder data collection unit and the system controller. Using CAN bus and CANopen protocol as data transmission object, implementing the CANopen protocol communication. It can be an intelligent node in CANopen protocol.The study include:(1) Proposing a design of the CAN bus transmission base on CANopen protocol for the Photoelectric encoder, design the bus structure of the framework and common bus type Photoelectric encoder scheme, analysising the principles of the CAN bus and CANopen protocol structure, lay the foundation for the Programming.(2) Design Photoelectric encoder hardware architecture and the hardware schematic. Including the power supply circuit, the input and output circuits and CAN bus communication interface circuit etc. Using the QEI module collecte the data which is output form encoder, using the CAN controller module for data transmission.(3) Programming for the node of encoder and CANopen protocol which is the focus of the study. It including Photoelectric encoder data processing procedures and CAN bus communication, CANopen protocol communication object and the object dictionary realization.Finally, building the Photoelectric encoder node test board and the entire CANopen network for testing Photoelectric encoder node, verify the data content and test communication function the results show that Photoelectric encoder node implements the functions which is expected.