1. Redundancy for OPC
using the
Cogent DataHub
(common scenarios)

2. No Redundancy
PLC OPC Server OPC Client
Process
• One process, one client
• Single data path (PLC and OPC server)

3. Redundancy – one computer
Redundant PLCs Redundant OPC
Servers
DataHub OPC Client
Process configured for
redundancy
• One process, one client, one computer
• Redundant data paths

4. Networked Redundancy
Redundant OPC DataHubs for Network
Redundant PLCs
or
Servers tunnelling Internet
Process DataHub for OPC Client
tunnelling and
redundancy
• Redundant data paths
• 2 OPC server machines, 1 client machine

5. Multiple Client Redundancy
DataHub OPC Client
Redundant PLCs Redundant OPC DataHubs for
Servers tunnelling
Process
DataHub OPC Client
• Redundant data paths
• 2 OPC server machines, 2 client machines

6. Multiple Client Redundancy
DataHub OPC Client
Redundant PLCs Redundant OPC DataHubs for
Servers tunnelling
Process
DataHub OPC Client
• Redundant data paths
• 2 OPC server machines, 2 client machines