The Zeno Alliance Network: a dual-loop fiber optic instrumentation network for ships

The Zeno Alliance Network (ZAN) is a dual-fiber, fiber-optic ring connecting any number of intelligent sensor interface (ISI) units to a central controller. Network devices transmit three-layer messages simultaneously in opposite directions around the loop, and each device has the ability to accept a message from either direction. In this way the loop is immune to breakage. Each ISI unit responds to its own address or to global commands. ISIs are capable of extensive data compression and operate on the network at 9600 baud. Thus collisions are rare, easily detectable, and resolvable. A recent ZAN installation is described. Four ISIs collect statistics of wind, air temperature, relative humidity, barometric pressure, and solar radiation from three different locations on the ship. The data are collected in a Microvax 2000 with a sophisticated database management system. Ship information is collected concurrently