Development Of Extended Alarm Based On CANopen Protocol

Recent years, CAN bus has been widely used in ship automation, providing reliableguarantee for ships’ operation safety. But due to the shortcomings of CAN bus, it’s difficultto get compatible with other higher-level protocols. CANopen protocol is the applicationlayer of CAN bus, which defines different message structures such as PDO, SDO and NMT.CAN open protocol can overcome the weakness of CAN bus. Thus, CANopen has broadapplication prospect.Ships’ extended siren is one of the important equipments for ships’ operation safety. It’svery important to develop extended siren which have friendly man-machine interface, highreliability, good inter-connectivity and strong real-time communication. In this paper, onetouch-screen extended siren is designed based on CANopen protocol. The system adoptsSTM32F103VBT6microprocessor as the control center, and convenient touch screen as thedisplay and operation interface,which is composed of main control unit and extended unit.The main control unit adopts redundancy design.According to the test, the system canmonitor alarm signal precisely, and display the alarm information in time, simultaneouslysending the alarm information to the assigned room. The system uses CANopen protocol inthe communication, which improves the stability and compatibility immensely. It’sbeneficial to generalize CANopen protocol in shipping field.In the thesis,CAN bus structure and its limitations are analyzed.Also,the modelCANopen protocol’s structure is analyzed. Then follow the modular design of hardware andthe analysis of each module’s anti-interference.After that,the software implementationsystem of CANopen protocol is analyzed.The software processing and corresponding codesflow is designed. Since CANopen network adopts bus arbitration mechanism, when networkload increases, the delay time of network transmission increases, as a result, the real timeand reliability of systems decreases. Therefore, this paper makes a further study about thereal time and reliability of system communication, and applied dynamic priority schedulingto improve the real-time of communication, the reliability of CAN bus is analyzed andresearched based on the research of CAN bus’ physical layer and network topology.The final test of the system indicates that the system can realize the monitoring, alarm,display and communication function of the master-slave unit, complying with CANopenprotocol. It meets the norms of China Classification Society. The system has friendly human-computer interaction interface, high inter-connectivity, real-time performance,reliability and compatibility. It’s worthy for generalized application.