The structure of CANopen protocol,communication object SDO and PDO in object dictionary are analyzed,and the application of CANopen protocol in dynamic moment testing system is described.

This paper introduces the basic framework, the object dictionary and communication objects of CANopen protocol,and explains the application of CANopen protocol in I/O modules,including the communication mechanism and communication framework of CANopen.

This paper will briefly analyze several important aspects of the CANopen protocol, such as object dictionary, communication object and network management, and illustrate them by some specific implementations.

After comprehensively reviewed the situation of digital object abroad, the paper analyzes the characteristics of hybrid digital object, and puts forward a reference model and defines the functions of five layers.

This document presents an infrastructure of digital objects in digital library, which provides persistent storage, secure access, management and index service to the distributed digital objects.

Raised the digital objects,especially the mature of digital storage technologies have greatly promoted the process of building a digital library.