OPC Failover Service Architecture for Process Control
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Solution Overview
Problem
Current OPC systems face challenges in maintaining redundancy and minimizing downtime due to server failures, with proxy server architectures introducing complexity, security issues, and potential performance reductions, as well as creating a new single point of failure.
Innovation Solution
An OPC Failover system architecture that monitors OPC servers for error conditions and redirects network communications by modifying object identifiers in the client's registry, allowing the client to reconnect to a different operational server without rerouting network traffic, thus maintaining transparency and avoiding the need for a proxy server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proxy OPC server architecture is used to provide failover capability, then redundancy and continuous operation are improved, but system complexity increases and a new single point of failure is introduced
Solution Approach 1:
The invention extracts the failover management functionality from the data path by implementing it as a separate service on the client node rather than requiring a proxy server in the data path. This removes the proxy server complexity while maintaining failover capability through direct server-to-client connections with backup routing logic.
Solution Approach 2:
The invention introduces a failover service as an intermediary component on the client side that manages server selection and failover logic without requiring a proxy server in the data path. This intermediary handles the complexity of redundancy management while keeping the data transmission path simple and direct.
2Reliability
If a proxy OPC server is implemented to handle failover, then server failure protection is improved, but performance decreases due to additional routing overhead
Solution Approach 1:
The failover management logic is extracted from the data path and placed on the client node, eliminating the proxy server routing overhead. Data transactions flow directly between OPC servers and clients without passing through an intermediate proxy, maintaining optimal performance while preserving failure protection capabilities.
3Reliability
If a proxy OPC server is used to provide redundancy, then failover capability is improved, but DCOM security configuration becomes more complex and potentially compromised
Solution Approach 1:
The security management complexity is extracted from the data path by implementing failover as a client-side service rather than requiring a proxy server. This maintains the existing DCOM security model without introducing additional security configuration complexity, as the failover logic operates within the client's existing security context.
4Loss of time
If the system is designed to minimize downtime through failover, then continuous operation is improved, but the system requires complex proxy server architecture
Solution Approach 1:
The failover service performs preliminary actions by pre-configuring backup server connections and monitoring server health proactively. When a failure is detected, the service has already prepared alternative routing paths, enabling rapid failover without requiring complex proxy server architecture to manage the transition.
Data Source
AI summary
This invention generally relates to computer systems and architectures, methods and computer program code for increasing the robustness of process control and manufacturing automation systems and the like, in particular to provide improved handling of error and/or failure conditions. We describe an architecture for an OPC Failover system, the architecture comprising: a plurality of OPC servers; at least one OPC client; a computer network linking said OPC servers and said OPC client; and an OPC Failover service coupled to said network and not coupled between said OPC client and said OPC servers, said OPC Failover service being configured to monitor at least one of said OPC servers for an error condition and to redirect network communications of said OPC client from one of said servers to another on detection of said error condition.