2008-08-20 14:35:06 -

Establishing mission-critical device networks that connect front-line PLCs to an Ethernet-based management system depends most on one thing: Redundancy. In this case, PLC failure is not the main concern. What worries most are the weakest, most vulnerable points in the system - the Ethernet connections themselves. To ensure robust fault tolerance, Ethernet network redundancy is the key.

Moxa now offers

a whitepaper dealing with the questions what type of Ethernet redundancy is suitable for different device networks and how to implement them.

Free download: www.moxa.com/Event/Tech/2008/Redundant_S2E_Campaign/index.htm

Excerpt:
Single-network redundancy includes STP/RSTP protocols for mesh-type topologies, and the proprietary Moxa TurboRing™ protocol for ring-type topologies. TurboRing™ for Moxa's NPort 6000 series of secure device servers supports a recovery time of under 100 milliseconds, compared to a recovery time of about 5 seconds for RSTP.

Dual-network redundancy includes Moxa's Redundant COM mode, which has a recover time of 'zero seconds' due to the fact that data is transmitted simultaneously over both networks.

Multi-host redundancy is set up to transmit the same data simultaneously to up to four hosts. The device server duplicates the serial data and transmits the data to all of the hosts at the same time.