Study Of The Detecting System For Ship Log Signal Transmitter Instrument Based On Virtual Instrument

Ship log is a kind of navigation equipments which is important forship driving. It can provide speed and range signal to calculate the ship’sposition. Signal transmitter instrument is the key module for shippositioning and navigation system which connecting the ship log and othernavigation equipments by speed and voyage data. It is important fordetecting the state of signal transmitter instrument because the state of thebridge has a significant influence on the projections of the displacement ofthe ship. During the detection, the signal connection and the sending andreceiving precision must be checked. Traditional hardware equipment can’tmeet the demand because of complex control signal and different outputsignal, and so far there isn’t any automatic detecting equipment for thismodule at home and abroad.To solve this problem, this paper provided an automatic detectingsystem for signal transmitter instrument based on virtual instrument whichadopting software instead of traditional hardware equipment. The basicprinciple of this system is that control signal was provide by signaltransmitter instrument and output signal of each interface was collected,the signal connection and the sending and receiving precision of thisinstrument under the setting conditions can be judged through thecomparison between output signal and standard library.The main work of this paper is designing the signal transmitterinstrument detecting system which included outputting control signal,collecting feedback signal, saving data and resolvers. During the design ofresolvers, the number of signals is large and sine/cosine analog signals fault characteristic is not obvious, so it is difficult to recognize the statesfor testing person. This thesis provided the method which resolving sineand cosine analog signals of resolvers into angle signals. This newresolving method was based on data acquisition, digital signal processing,anti-trigonometry and LabVIEW. Through experimental validation thismethod is low-cost, high precision and convenient operation. Becausesignal transmitter instrument contained two types of excitation voltageamplitude of resolvers, this paper proposed the module which wasconsisted of MCU and500Hz excitation source and integrated on thecircuit board. The module reduced the cost and saved the internal spaceand improved the reliability of the system.The subject preferred virtual instrument to traditional detectingequipment, the system has friendly interface and fully detecting functions,it is light-weight, efficient, and easy to using for the testing personnel.Through the experiment in actual ships, it carried out that signaltransmitter instrument was accurate and reliable and reduced the workloadand improved the efficiency of fault diagnosis. This subject provided aneffective way for related electrical equipment state detection.