Design And Research Of Scientific Instrument Interface Module (SIIM) Based On Embedded PC

The cabled seafloor observatories play an irreplaceable role in long-term, continuous, real-time, in-situ observation of ocean. The study of cabled seafloor observatory began at the beginning of this century in our country, and now it’s still in the infancy.The layered network model proposed in this issue divided a cabled seafloor observatory into5layers:Instrument Layer, Access Layer, Convergence Layer, Backbone System and Onshore System and defined the function of those layers and the interfaces between them. And there are three types of cabled seafloor observatories according to their scale:local cabled seafloor observatory, regional cabled seafloor observatory and global cabled seafloor observatory. Various solutions derived from the layered model are able to meet different needs of seafloor observation.Two types of SIIM (Scientific Instrument Interface Module) were developed based on the definition of the layered network model and the requirements in Z2ERO (ZJU-ZRS Experimental Research Observation). SIIMs with48VDC&copper Ethernet interface provide the connectivity between instruments and science node within100m, while SIIMs with375VDC&optical Ethernet provide the same connectivity within thousands of meters. Each SIIM is able to provide10instrument ports with replaceable various interfaces. The control system of SIIM monitors the status of SIIM as well as the instrument ports and protects the instruments connected in with software&hardware overvoltage and overcurrent protection.The reliability indexes of SIIM’s modules are distributed based on its mission reliability model and those indexes are regarded as the basis of equipments selection as well as the design constraints of SIIM’s components. When the design is completed, the parts count modeling and parts stress modeling is used to predict the reliability of SIIM and identifies vulnerable parts. After that, the overall reliability of SIIM is improved by raising the quality level of vulnerable parts.A layered network model of cabled seafloor observatory is proposed is based on the experiences from the domestic and abroad and as an implementation of access layer in the model, SIIM is developed based on embedded PC. Reliability distribution and prediction techniques are used to analyze and ensure the reliability of SIIM. SIIM is proved to be a successful device of access layer by passing the pressure test of the cavity, the calibration test of circuits, the system test, the tank trial, the lake trial, and the sea trial.