Redundant Power and Communications on a Single Cable

Presents a method to provide redundant power and communications on a loop of cable, connecting 24 or more sensor systems. The power is distributed direct c u r r e n t , w i t h a c e n t r a l b a t t e r y Uninterruptible Power Supply ( O P S ) . Communications are provided via bidirectional data paths. A 100% redundant power loop is three AWG 10 conductors and two shielded pairs, coextruded in a buriable sheath. Cutting a combination cable does not disable a looped system, since voltage drops will be c o m p e n s a t e d by i n d i v i d u a l DC/DC converters. A short from any single power conductor to ground shall cause a circuit breaker at the head-end to trip, removing the fault from the system. Diodes at e a c h Processor i s o l a t e the f a u l t . Supervision circuits signal the voltage imbalance. A bi-directional multiplexed addressable transponder at each Sensor accepts 8 alarm inputs. In the event of local failure, that transponder is bypassed. Head-end Cable Power is 48 volts DC, trickle charging a 48 Volt Battery. DC to DC Converters, with a nominal input voltage of 48 VDC (+50*) provide a regulated 15 VDC at up to 0.8 Amps at each Processor. Local backup batteries may be provided at each sensor to allow redundant backup.