Rockwell Automation Publication ENET-AT003B-EN-P - June 2014 41
Troubleshoot Embedded Switch EtherNet/IP Networks Chapter 5
Rapid Ring Fault When a Rapid Ring Fault occurs, the following events occur:
• The active supervisor blocks traffic on port 2, resulting in possible network segmentation, that is,
some nodes can become unreachable.
• The Link 2 status indicator on the active supervisor is off.
• As soon as the fault occurs, for both Logix Designer application and RSLinx Classic software, the
Status field = Rapid Fault/Restore Cycles.
Any of the following can cause a Rapid Ring Fault:
• 5 intentional disconnections/reconnections of a node from the network within 30 seconds
• A duplex mismatch between two connected devices
• Electromagnetic noise on the network
• Unstable physical connections, such as intermittent connectors
Given the nature of a Rapid Ring Fault, the Last Active Node information can be inaccurate when a Rapid
Ring Fault condition is present
Multiple possible solutions exist.
• For the disconnections and reconnections
issue, no solution is required.
Clear the fault when you have reconnected the
device to the network permanently.
• For the duplex mismatch issue, reconfigure the
duplex parameters to make sure that they
match between the devices.
• For the electromagnetic noise issue,
determine where the noise exists and
eliminate it or use a protective shield in that
location.
• For the unstable connections issue, determine
where they exist on the network and correct
them.
• Check the media counters for all devices on the
network. The device with the highest media
counter count is most likely causing the Rapid
Ring Fault.
• Remove devices from the network one by one.
When you see the Rapid Ring Fault disappear
after a device is removed, that device is
causing the fault.
• You can use Device Port Debugging Mode
functionality on the 1783-ETAP tap to analyze
a suspicious node.
• Finally, your Beacon Interval or Timeout
configuration can be inappropriate for your
network.
However, if you think you need to change
these values, we recommend that you call
Rockwell Automation technical support.
Once the fault is fixed, click Clear Fault.
Partial Fault
Condition
A partial network fault occurs when traffic is lost only in one direction on the network because a ring
member is not forwarding beacons in both directions for some reason, such as because of a component
failure.
The active ring supervisor detects a partial fault by monitoring the loss of Beacon frames on one port and
the fault location appears in the Ring Fault section of the Network tab.
When a partial fault is detected, the active ring supervisor blocks traffic on one port. The ring is
segmented due to the partial fault condition. The nodes near the faulted part of the network are
displayed in the Ring Fault group with either IP addresses or MAC ID’s for each node displayed.
When this fault occurs the Network Status field = Partial Fault Condition.
Once the fault is corrected, it automatically clears, and the Network Status field returns to Normal.
Determine where the fault condition exists and
correct it.
Use Device Port Debugging Mode functionality,
also known as Port Mirroring, on a 1783-ETAP,
1783-ETAP1F, or 1783-ETAP2F tap to analyze a
suspicious node.
Table 11 - Troubleshoot Specific Network Issues (Continued)
Issue Description Solution