Fault-tolerant loops for distributed measurement systems

A family of fault-tolerant loops, known as skip-braid networks, based on simple 2-input 2-output switching elements (or nodes) is proposed as an interconnection scheme for low-level devices in distributed measurement systems. These networks offer a degree of fault tolerance limited mainly by the allowable cabling overhead. Network scanning and reconfiguration routines are described which can locate and bypass network faults in a time comparable to a typical network polling period. It is shown that these routines can be adapted to suit a variety of skip-braid networks, and because both are based on a simple Boolean matrix representation of the network they are easy to implement. The performance of a prototype system that uses optical fibre data links and battery-powered remote nodes is discussed.