Electronics for multiple sensor/control element cabled systems

As underwater installations become larger and more complex, the number of electronic modules required and their physical dispersion increases. These modules may be sensors, such as water current meters, pressure sensors and accelerometers, acoustic devices such as hydrophones and acoustic ranging devices, and modules that provide electronic control. Communications and power must be provided to each. The power and bandwidth requirements of the individual modules, and whether they are senders or receivers of information, or both, may be quite different. The number of modules of each type, and their physical separation, will generally be different in different installations. The problem is to provide a system for communications and power that is flexible in application, physically and electronically rugged, and long life. This paper describes a communications and powering system that meets these objectives. In this system the electronics modules are interconnected with a single coaxial cable. Each module connects through a multiplexer and a Tee-splice to the cable. The cable, multiplexers, and Tee-splices provide both power for the modules and one or two-way communications with them. Distances between the modules can range from a few feet to thousands of feet. Up to several hundred modules can be accommodated.