Real-time ocean observing systems provide critical information for the study of ecosystems, water quality, and fisheries, as well as data for long-term climate change studies. Sea-Bird's Inductive Modem (IM) system for moorings provides reliable, real-time data transmission for up to 100 instruments that can be positioned or repositioned at any depth, without the use of cable connectors. IM moorings use standard plastic-jacketed wire rope as both the transmission line and mooring tension member. The heart of the IM system is an Inductive Modem Module (IMM) or Surface Inductive Modem (SIM) that communicates with the bouy controller and with the underwater instruments. The IM system can accommodate a wide variety of instruments for nearly any type of measurement. Sea-Bird manufactures IM versions of a number of instruments, measuring various combinations of temperature, conductivity, pressure, dissolved oxygen, and data from integrated auxiliary sensors. Also available are devices that allow RS-232 output instruments from other manufacturers to be integrated with an IM system.
Application Note 92 provides background information on inductive modems, principles of inductive coupling, mooring configurations, use in fresh water, system components, mooring cable and cable fitting resources, and a summary of OEM components available from Sea-Bird. Real-Time Ocean Observing Systems with Inductive Modem Telemetry Technology, published in Ocean News & Technology, provides information on customer applications.
Sea-Bird has a large number of instruments intended for real-time ocean observing systems. See our complete list of Moored/Time Series instruments, including IM instruments as well as RS-232 and RS-485 output instruments.