Does OPC Bridge in OPC Expert support hot standby redundancy so that data transfer continues automatically if the primary server fails?
Yes, OPC Expert supports hot standby redundancy as part of its built-in redundancy capabilities. When a primary OPC server becomes unavailable, OPC Expert can automatically failover to a secondary server without manual intervention, keeping data transfer running continuously. This applies to bridging scenarios as well as other OPC Expert features that rely on persistent server connections.
Hot, Warm, and Cold Redundancy Options
OPC Expert’s OPC Redundancy module provides three redundancy modes. Hot redundancy keeps a live connection to both the primary and standby servers simultaneously, allowing an immediate switch with no reconnection delay when the primary fails. Warm redundancy maintains awareness of the standby server and connects quickly upon failure, with a brief transition period. Cold redundancy keeps the standby configuration ready but does not establish the connection until it is needed. The appropriate mode depends on how much transition time your application can tolerate and what the standby server’s connection behavior supports.
Automatic Failover and Failback
When OPC Expert detects a loss of connection or data staleness on the primary server, it switches to the standby server automatically. This does not require an operator to intervene or restart any services. Optionally, OPC Expert can also be configured to return to the primary server automatically once it comes back online, which is known as automatic failback. This keeps the system operating from its preferred data source whenever it is available, without requiring manual monitoring.
Custom Failover Triggers
Beyond simple connection loss, OPC Expert allows you to define custom trigger conditions for failover. These can include data staleness thresholds, value deviations beyond a specified range, or other conditions that indicate the primary server is producing unreliable data even if the connection itself is technically active. This level of configurability is important in environments where a connected but malfunctioning server would cause more harm than a clean failover to a known-good standby.
Relevant Tools
OPC Redundancy is the dedicated OPC Expert module for managing hot, warm, and cold failover between primary and standby OPC servers. It works alongside OPC Bridge to ensure that the data transfer path remains intact even when the underlying server infrastructure experiences failures. The visual drag-and-drop interface in OPC Expert makes it straightforward to configure which servers participate in a redundant pair and under what conditions the switch should occur.
Hot standby redundancy in OPC Expert is a reliable approach for environments where continuous data availability is non-negotiable. The combination of automatic failover, configurable triggers, and optional failback means the system can be tuned to match the specific reliability requirements of your process.