Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual page 235

When the "Error (Illegal ring connection detected/Execute loopback)" icon is displayed
When the "Error (Illegal ring connection detected/Execute loopback)" icon is displayed in "Network Status", take following
actions.
■When the system does not contain a switching hub
The network is configured in ring topology although "Network Topology" of "Basic Settings" is set to "Line/Star".
Take any of the following actions.
Action
Disconnect an Ethernet cable connected to any station on the network (either P1 or P2).
The network topology will become a line topology and data link will start.
To configure the network in a ring topology, take following action.
• Set "Network Topology" of "Basic Settings" to "Ring" and rewrite the parameters to the CPU module.
• Check that the master station on the master station supports the loopback function. To check whether the module supports the loopback function, refer to the
user's manual for the master/local module used.
■When the system contains a switching hub
The "Error (Illegal ring connection detected/Execute loopback)" icon is displayed due to any of the following causes.
• The network is configured in ring topology although "Network Topology" of "Basic Settings" is set to "Line/Star".
• The network is configured in star topology although "Network Topology" of "Basic Settings" is set to "Ring".
• A switching hub is connected when "Network Topology" of "Basic Settings" is set to "Ring".
Take the following actions.
Action
1.
Check if "Network Topology" of "Basic Settings" is different from the network configuration. If so, correct "Network
Topology" of "Basic Settings" and rewrite it to the CPU module. When data link starts across the entire network, this
procedure is successfully completed.
If data link does not start, perform step 2 and 3.
2.
When "Network Topology" of "Basic Settings" is set to "Line/Star", take the following actions.
• Disconnect one Ethernet cable connected to the switching hub and power off and on the hub. (Repeat this operation until
data link starts over the network.)
• When data link starts over the network, check the network configuration using CC-Link IE Field Network diagnostics. The
procedure is successfully completed. ( Page 223 Checking the Network Status)
3.
When "Network Topology" of "Basic Settings" is set to "Ring", take the following actions.
• Configure the network in ring topology without a switching hub. Connecting a switching hub will cause a problem such as
data link failure. ( MELSEC iQ-R Ethernet/CC-Link IE User's Manual (Startup))
• Check that the master station on the master station supports the loopback function. To check whether the module
supports the loopback function, refer to the user's manual for the master/local module used.
4 TROUBLESHOOTING
4.3 Checking the Network Status
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