Ship Network Intelligent Detection Devices

Nowadays the monitoring and control systems based on DCS have been widely used in marine engine rooms. However the DCS-based monitoring system can not perfectly meet the requirements of the reliability, maintainability and interoperability owing to its complicated structure and devoted communication stations. The field-bus control system (FCS) suggests a new way to solve these problems. Generally a FCS consists of a series of intelligent nods such as sensors or actuators. The intelligent field-bus sensors, known as the intelligent networking sensors, could be simply and easily connected with other nods to build up a FCS- type of monitoring system for the marine engine room. In this dissertation, the design of a kind of intelligent networking measuring device is presented for the applications of the marine engine rooms. This design is based on the LonWorks which is a kind of field-bus technology widely used all over the world. This device takes the Neuron Chip 3150 of Motorola as its central unit, on which the external memory, A/D converter, keypad, the display unit, etc are assigned. This intelligent networking measuring device can be used as an intelligent node in the monitoring system of the marine engine room. The design schemes for its hardware pieces are proposed, the software programs are developed and tested by the experiment data. In order to improve the precision of the intelligent measuring device, the proper compensation is necessary. This problem is investigated in this dissertation with the automatic compensation methods being proposed. For the case of temperature measurement, the method of compensation for the sensors non-linearity is set up, with which the non-linear curve is approached by piecewise lines. The optimal approaching method is introduced. For the case of pressure measurement, the compensation method is also built up against the shift of the environment抯 temperature. The variable-coefficient regression method is applied, resulting in a matrix representing the compensation coefficients. Such matrix could be stored in the EPROM of the intelligent measuring device and utilized to realize the compensation. The necessary data for this regression is obtained via test. In such method, the temperature stability of the intelligent device is remarkably enhanced, as shown by analysis. The function of the automatic fault diagnosis can effectively enhance the ii reliability and security of a measuring device. Based on the fuzzy logic, the classification method is proposed to achieve the diagnosis of the intelligent networking device's fault. To describe the possible fault's mode, a symbolic function is defined. It can be identified by a fuzzy logic system. Simulation proves its correctness. The field-bus technology brings the new concept of intelligent networking sensor. Consequently, the intelligent networking sensor, if applied in the marine engine room to build up a FCS-based monitoring and control system, will produce much greater benefits. The design scheme described in this dissertation is partly tested in lab. However, there is still a long way to go to make a product of such device.