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Industrial Ethernet Book 105

means that if there is one cut in the cable then all communications are lost to every node beyond that point. So, if network reliability is paramount to your application, then you should consider other topologies. One topology that can greatly improve your networks reliability is a star topology. This topology is more expensive because it requires additional hardware. However, it has many benefits that justify the additional cost. In this configuration, each node is connected to a hub or switch that is connected to the controller. This structure increases the reliability since a failure in a single servo amplifier, inverter or I/O block will not disrupt the entire network. In some cases, you can “hot swap” an axis without affecting the rest of the network. Depending upon the number of nodes in your network adding one or more hubs or switches can potentially increase the cycle time of the network. Another added benefit of this topology is modularity. Since the hubs or switches allow nodes to be added or removed without disrupting the entire network, an engineer can design a very modular machine. In the case of Yaskawa’s Mechatrolink III network, hubs can be used to create a star topology or even a hybrid star and cascading bus topology. Each hub for Mechatrolink III can support up to 8 nodes. The nodes can even be cascaded to another level. However, there can only be two hubs between any node on the network and the controller. The Mechatrolink III network It needs the application program to stop and start the control to the slaves which replace and/or add. System B can support up to 62 nodes. These features allow an engineer to create a network that is optimized for cost, speed and reliability. Jerry Tyson and Michael Miller, Yaskawa America, Inc. Simplify Machine IP Integration Maintain your factory-set IP addresses when integrating with the customer’s IP network by using the EIPR IP Router. • Reduce installation time • Eliminate IP conflicts • Easily comply with your customer’s IP requirements Learn more at www.ccontrols.com/machine EIPR IP Router Master HUB System A Replace Add Depending on the nodes in a network, adding one or more hubs or switches can potentially increase network cycle time. SOURCE: YASKAWA Technology


Industrial Ethernet Book 105
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