The Design Of Safety, Monitoring And Alarm System And Test Platform With Marine Diesel Engine

The broad application of digital and bus technology in ship industry drives the ship automation to advance fast. The Safety, Monitoring and Alarm System (SMAS) for marine diesel engine is an important content of ship engine room automation. The research and design about it is helpful to improve our country's technique level in ship auxiliary equipment.Based on the exploration about the working features and test demands of a L21/32 marine medium-speed diesel engine and consideration about engineers' operation habits, the SMAS is made up of several modules, among which the RS485 bus is adopted. These modules are all independent and desperate to secure the diesel engine. This thesis has also developed a set of test platform for SMAS, which tests SMAS through virtual instruments based on NI PXI system.Some works have been conducted in this thesis mainly as follows:1) To develop safety system. According its control objects, the input/output arguments and corresponding I/O points are confirmed, hence the control units are selected. The research has been done about the use of AC1131 software, the definitions of variables, the extensions of function library and the fault detection about sensors'wire break. Having analyzed the errors and its causes of high-speed sampling, the revolution value are corrected2) To design the function of test and control platform's hardware and software. According to the type and scope of signals from sensors, the virtual instrument test system is built, which is composed of FPGA, NI analog and digital modules. Through Lab VIEW application program interface of VISA the prototype machine's crucial parameters are obtained from RS485 bus, then classed, bundled and scaled, they are changed into the signals which can be output precisely by FPGA.3) The I/O and alarm objects processed in base module are researched. In addition, the research also includes the principles of the electrical source in bus, the interface circuits of sensor, on-off and analog signals regulation circuits and bus interface circuits, the formation logic of important alarm points and MODBUS protocol criterion. 4) The system functions are vertified by variable-frequency motor driven toothed disc and high speed digital module of NI 9401, the safety system is doubly tested to ensure the system to work properly. Using FPGA data acquisition technology, the monitoring and alarm system is tested.