I'm evaluating methods of implementing OPC communication between DeltaV 14.3.1 and a 3rd party DCS and ensuring decent availability against downtime. Additionally I am seriously considering an OPC tunneler to reduce DCOM issues across multiple network segments and increase security. However I am running into some grey areas and any advise would be appreciated. So, for the following:
- DeltaV OPC DA (Server)
- 3rd party OPC DA (Client)
- As of yet to be chosen tunneler (desired local OPC transactions rather than local for better network resistance)
I see 2 main paths forward
Native DeltaV Redundant OPC Servers
Seems the simplest and most Emerson supported method. 2 Application stations, set and licensed as redundant with automatic failure recover setup. However, it appears a THIRD station is required to have OPCRemote and then Redundant Handler installed. So the OPC servers themselves have higher availability but the Redundant Handler itself is now back to a single point of failure. I believe I would install a tunneler on this third station to access the overall OPC server and then serve it to the network. I see no way around the third station being a single point of failure apart from using ESXI/HyperV with a failover on the VM itself and multiple NICs on the same segment to allow network fail over.
Multiple DeltaV Servers With External Redundancy Manager
Set up 2 app stations as above as OPC servers and handle the redundancy with a 3rd party solution. This again involves a third machine, which would handle the fail over between the two. The main benefit here being that I could source a product that is both an OPC redundancy manager and tunneler in one. Seems to be the same hardware issue as above and would need some way to protect against the third machine from failure. Main benefit here being ease of integration of a tunneler, and potentially more control over the fail over conditions, etc. However I don't know if 2 non-redundant OPC servers load the DeltaV network differently than a native redundant pair.
If there's other reasonable configs for server-client access through OPC tunnels I'm all ears!
In reply to Bruno DB:
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