Mitsubishi Electric MELSEC SW1DNC-CCIEF-B User Manual page 27

Configuration in which data link cannot be performed (incorrect ring topology)
Do not wire devices as shown below. Doing so will cause an error in all stations and data link cannot be performed.
• Connecting both PORT1 and PORT2 to the switching hub
• Ring topology through a switching hub
Ring topology
To configure a network in ring topology, set "Use" for "Loopback Function Setting" in the Network Parameter screen for the
master station. (Page 102 Supplementary setting)
When a module is used for the master station, check if the module version supports the loopback function.
MELSEC-Q CC-Link IE Field Network Master/Local Module User's Manual
■Configuring a network in ring topology using a switching hub
If a network is configured in ring topology through the two ports of the switching hub, the following problems may arise.
Therefore, do not use a switching hub for ring topology.
• Loopback cannot be detected if an Ethernet cable is disconnected.
• If a station is disconnected due to failure or power-OFF, data link will stop.
Switching hub
Switching hub
Switching hub
Cannot connect both Ethernet ports
to the switching hub.
2 SYSTEM CONFIGURATION
2.2 CC-Link IE Field Network Configuration
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