US 7,454,252 B2Granted

Redundant fieldbus system

AssigneeMoore Industries International, Inc.

InventorHassan M. El-Sayed

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Abstract

A redundant fieldbus system provides power and communications in a parallel physical configuration between the host system and attached field devices irrespective of any single point failure in the network. In case of a fault, the redundant fieldbus system automatically eliminates the faulty section of the network, switches power and communications to the healthy portion of the network and terminates the network for signal integrity. A device coupler for the system may include a fault detector coupled to an auto-termination circuit that terminates a fieldbus cable when a fault is detected. The device coupler may include fault detection and isolation coupled to each set of spur terminals used to connect field devices to the device coupler. A field device for the system may include circuitry for deselecting a faulty cable while maintaining connection to a healthy cable.

Claims16

Dependent claims

An apparatus for use in a redundant fieldbus system, the apparatus comprising:

first terminals adapted to connect to a first fieldbus cable, the first terminals coupled to a field device to provide power and communications from a fieldbus network to the field device;
second terminals adapted to connect to a second fieldbus cable, the second terminals coupled to the field device to provide power and communications from the fieldbus network to the field device;
and
isolation circuitry connected between the first terminals and the field device and connected between the second terminals and the field device, the isolation circuitry adapted to provide power from either the first terminals or the second terminals to the field device, the isolation circuitry further adapted to isolate a short circuit between the first terminals from a power source connected to the field device through the second;
and
wherein the apparatus provides independent current paths between the first terminals and the field device and between the second terminals and the field device, the apparatus further comprising first and second spur connection circuits.

3 more elements

Dependencies are inferred from the claim text.