Issue
The standby PLC switches momentary to NOCONF as part of the process of updating the application (transfer from Primary to Standby after an online changes). This creates a loop with the external switch, flooding the network with ARP messages and creating a communication issue with a drop.
Product line
Modicon M580
Resolution
In a specific configuration, where the service port of both CPUs in a HSBY system are connected at the same switch, is necessary take an extra step to avoid the loss of communication with RIO drops when is being transferred from the Primary CPU to the Standby CPU. The recommended solution for this case is the usage of VLANs
Additionally, enable the option Automatic blocking of service port on Standby CPU at Control Expert application.
With this approach, the PLCs service ports will be completely isolated but still can communication with external devices.
The standby PLC switches momentary to NOCONF as part of the process of updating the application (transfer from Primary to Standby after an online changes). This creates a loop with the external switch, flooding the network with ARP messages and creating a communication issue with a drop.
Product line
Modicon M580
Resolution
In a specific configuration, where the service port of both CPUs in a HSBY system are connected at the same switch, is necessary take an extra step to avoid the loss of communication with RIO drops when is being transferred from the Primary CPU to the Standby CPU. The recommended solution for this case is the usage of VLANs
Additionally, enable the option Automatic blocking of service port on Standby CPU at Control Expert application.
With this approach, the PLCs service ports will be completely isolated but still can communication with external devices.
Released for:Schneider Electric Canada
