This article from InSource shows...
- Author: Peter Farrell
- Published: 12/16/2021
- Applies to: Application Server all versions
If, in a redundant IO environment, the System Management Console is filling with informational level messages which show a redundant topic partially connected and then connected, you may need to consider changing the configuration and/or architecture.
The logger messages may look similar to the following.
Status of Backup DI source [MyRedundantIOSource] is Partially Connected
Status of Backup DI source [MyRedundantIOSource] is Connected
There are a couple of reasons that you may see the repeating informational messages advising of a partial connection and then connection.
- You may have more then one PLC (topic/device group) included within a single redundant IO object. The problem with such an architecture is that if one of your PLCs is down, the object will then show a partially connected status.
- You may not have defined a ping item for your topic/device group. Under this circumstance, the system will choose a ping item which may itself not be a good choice and become unavailable. You should always specify a ping item.
Shown below in the screen shot is a configuration of a redundant DI Object which includes more than one PLC and no ping items defined for the scan groups.
If possible, each Redundant DI Object should contain only a single PLC/Device/Scan Group and you should identify a PLC IO item which can be used for each device group/scan group defined for that PLC.
In the example shown below, the configuration/architecture has been changed such that the object hosts only a single PLC and each scan group has been configured for a ping item, which is a PLC item reference. Failure to add a ping item can result in unnecessary failover conditions.