Controller AC 800M OPC Connections
We moved a pair of AC800M OPC servers off of a combined aspect/connectivity server and created a new dedicated connectivity server due to resource allocation in the ASCS and future expansion.
The controllers were in a production mode during this handover and couldn't be reset in this process. There was a brief period when the controller was communicating to both connectivity pairs.
Now that the old pair of OPC servers has been completely removed, I would like to lower the "max number of subscriptions" to the two working connectivity servers, but I am not sure how the controller decides which connection(s) will be removed. Is there a way to select which OPC connections should be removed? Does this require a controller reset? Anyone familiar with how this is handled?
After disconnecting the OPC server from the controllers the corresponding AE subscriptions should be cancelled and the queue slot be freed.
Have you looked at the AE subscription tab of the SystemDiagnotics block of concerned controllers?
If everything worked as it should, the overshooting queue slots are now empty and you should be able to reduce them at next download.
In older firmware versions, a controller reset could sometimes become required to have the AE subscription removed.
The number of subscriptions is only used for the alarm and event connection.
It is possible to check the number of used connections and subscribing systems, using the "System Diagnostics" FB-interaction window/Advanced/Alarm Event.
You will most probably find that only the remaining subscribers are connected.
On the other hand, leaving the "Max no of subscribers" on a higher value than 2 will not be a problem.
It is possible to download the change as a warm download.