Expendable Conductivity/temperature/depth Measuring System Used On Ship

Marine's eXpendable Conductivity/Temperature/Depth Profiler (XCTD) is a disposable measuring instrument which mainly used to measure water temperature, conductivity and salinity. Such equipment provides advanced measurement methods for marine surveys, scientific research and military applications. As the foreign perform XCTD technology blockade against our country, we can not purchase the XCTD device through normal channels at present, in order to develop our country engineering in disposable equipment and to meet international standards, the National Ocean Technology Center begin a large-scale research projects of XCTD system under the special foundation of National Plan Items of "863".The highlight of this paper is the designation of underwater data acquisition system and the host computer data monitoring and management software system board . Firstly, according to the overall performance requirements of XCTD's probe dropping fast and have high resolution, to reduce the time constant, improve the accuracy and the sensor's long-term stability as the goal, select the appropriate temperature sensor and conductivity sensor components to complete the research of sensor circuit design method in the probe. Secondly, the underwater data acquisition system uses AT89S52 microcontroller as the control core, and completed its design of external circuit. In order to reduce the cost of disposable equipment investment and improve the measurement accuracy, using high-precision 16-BitΣ-ΔA/D converter AD7705 chips to carry out A/D conversion for collected signals. Using serial communication means for data transmission. Thirdly, the microcontroller's working program prepared by C51 language, mainly including the module of microcontroller serial port initialization, the control module of AD7705 registers, data reading and writing modules, and serial communication module. Finally, designed the host computer software system in the Visual C++6.0 environment. With MSComm control, GDI, DAO access to databases and other key technologies, developed the real-time data acquisition monitoring software with full-featured, simple operation and friendly man-machine interface. The corresponding codes and comments are also given. Working performance of the software system is very stable, with the underwater data acquisition system together constitute a complete monitoring system.The development of deep-sea thermohaline data monitoring system has been tested, the results of tests show that the design and research have high reliability, good real-time, and high portability features. This design and research in line with the actual situation and requirements use in the field, and plays a significant role in the XCTD system.