Low cost redundancy technology [dual homing

Abstract

Dual homing has long offered the potential to add redundancy to plant floor automation systems for reduced downtime - but only at a cost that put it beyond all but the most critical installations. Now a new technology is bringing the benefits of dual homing to mainstream control applications without the associated costs. Effective redundancy strategies have always been of prime importance in critical applications where a fault or failure could result in catastrophe. But today even in more standard industrial applications, the simple financial costs associated with unexpected downtime are leading increasing numbers of manufacturers to look at introducing redundant systems to deliver the high availability needed to ensure profitability. Designing and implementing high availability industrial networks has traditionally represented something of a challenge. While dual homing has long provided a conceptually simple means of achieving high levels of redundancy, actually implementing such dual homing within an Ethernet network has traditionally relied upon having the dual homing functionality within the critical node itself - a PLC, industrial controller, sensor, etc.