REDUNDANCY at the edge of industrial networks is greatly simplified by the new dual-homing Magnum ESD42 switches, available from Dewar Electronics.
These simple, unmanaged switches offer convenient plug-and-play dual connectivity in a physically small package (about the size of a fist) and they are hardened and rugged for use in any industrial environment.
With a MTBF of more than 30 years, they provide high reliability to enable redundancy for nodes at the edge of the network at a low cost.
Designing and implementing high-availability Ethernet LAN topologies in industrial networks can be challenging. The serial field buses that have been traditionally used for industrial control do not offer fault-tolerant options and industrial systems designers are not accustomed to planning for redundancy for control devices.
In the past, the choices for redundancy for edge-of-the-network devices were too limited, too expensive and too complicated to be considered in most industrial systems.
Today, however, high availability is becoming a key component in many industrial environments. Stopped manufacturing lines, power outages and other system failures are becoming much too expensive – and visible – to tolerate.
While ring and mesh topologies for connectivity are coming into more general use, finding practical ways to provide for recovery from faults for edge devices and nodes has remained difficult.
The software required to manage computers and other devices that have dual NICs for redundant connections into the network is complex and the dual-NIC solutions are costly.
Very few manufacturers offer PLCs and IEDs with dual connectivity built in for industrial sensor and controller applications. GarrettCom Inc.’s new dual-homing technology (patent pending) in small industrial Ethernet switches is changing the picture.
What is dual-homing?
In Ethernet LANs, dual-homing is a network topology that adds reliability by allowing a device to be connected to the network by way of two independent connection points (points of attachment).
One access point is the operating connection and the other is a standby or back-up connection that is activated in the event of a failure of the operating connection.
A dual-homing switch, with two attachments into the network, offers two independent media paths and two upstream switch connections.
Loss of the Link signal on the operating port connected upstream indicates a fault in that path and traffic is quickly moved to the standby connection to accomplish a fault recovery.