The Design And Implementation Of The DPU In Marine Engine Room Monitoring And Alarm System

As one of the most important parts of ship automation equipment, ship’s engine room monitoring and alarm system can implement real-time monitoring of devices in the engine room, so as to guarantee the safety of navigation. A complete monitoring and alarm system contains three parts:(1)Sensors distributed in throughout the engine room.(2)Control cabinet and surveillance equipment or monitor screen installed in the control room.(3)Extended alarm boxes installed in the Bridge, public places, chief engineer and engineer bedroom.DPU (Distributed Processing Unit) are designed as modularized intelligent field I/O units with communication capability. It’s the core of the monitoring and alarm system. Hundreds of DPU distributed throughout the engine room. DPU connected to the sensors or actuators directly. Has the ability to monitor parameters, alarm and control independently. In this paper, the DPUs are designed including the digital input module, digital output module, analog input module, analog output module, RTD signal input module base on MSP430F149, with dual redundant CAN bus communication. And the function of signal conditioning, data processing, and CANopen communication is realized.Firstly, based on the "Shipbuilding Industry Standards of the People’s Republic of China" and the "Rules for Classification of Sea-going Steel Ships" and literature, the overall design scheme and the function of each module are given. Including three parts, signal acquisition, signal processing, and dual CAN bus communication. CAN bus communication section follows the CANopen protocol.Secondly, hardware schemes are designed. Micro-controller MSP430F149, CAN control chip MCP2515, and optical isolation with ADUM1201 to protect post-stage circuit. Digital input module, digital output module, analog input module, analog output module and RTD input module are designed within Altium Designer environment. Digital input and output modules realized the function of switch input and output. Analog input module using the ADC integrated in MSP430F149 to realize digital to analog conversion. Get the digital data. Analog output module uses TLC5628 chip, to realize digital to analog conversion, get the analog output. The RTD Input Module using a Wheatstone bridge and op amp circuits for signal conditioning, to get the desired signal.The software is programmed by C language in the IAR environment, realized CAN bus communication in the CANopen protocol, In full compliance with the maritime standards, at last, build the 5 modules up to form a network.Finally, connected by the CAN bus communication network, each module of the main engine remote control system is transformed to the hardware platform. And so a complete remote control system is implemented.By test the CAN network, the acquisition precision, redundant CAN bus communication performance have reached the standard for ship device detection.