OPC Server Redundancy Management for Process Control
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Solution Overview
Problem
Existing process control systems, such as SCADA systems, face delays in switching between redundant components, leading to temporary service disruptions during switchover, making them less reliable and more complex to implement and maintain.
Innovation Solution
The redundancy management is handled by the OPC server rather than the OPC client, with a single OPC server facilitating communication between redundantly operated control devices, allowing for efficient role determination and data synchronization to ensure rapid switchover and continuous process control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy management is handled by the OPC client with multiple OPC servers, then system reliability is improved through redundant operation, but the switchover time between redundant components increases, causing service disruptions
Solution Approach 1:
The patent inverts the traditional architecture by moving redundancy management from the OPC client to the OPC server. Instead of the client managing multiple servers and performing switchover decisions, a single OPC server handles redundancy management and performs switchover between control devices, dramatically reducing switchover time while maintaining reliability
Solution Approach 2:
The patent extracts the redundancy management function from the OPC client and concentrates it in the OPC server. This separation allows the client to focus on process control while the server handles redundancy coordination, enabling faster switchover operations without burdening the client system
2Reliability
If multiple OPC servers are used for redundant operation, then system reliability is improved, but the complexity of implementation and maintenance increases
Solution Approach 1:
The patent merges the redundancy management functionality into the OPC server, consolidating what would otherwise require multiple independent OPC servers with separate management logic. This unification simplifies the system architecture while maintaining redundant operation between control devices
Solution Approach 2:
The OPC server is designed to perform multiple functions: it handles both the primary process control communication and the redundancy management tasks. This multi-functionality eliminates the need for separate redundancy management components, reducing overall system complexity
3Reliability
If the OPC client performs switchover detection and selection, then redundant operation is achieved, but the time required for detecting switchover and providing new process variables increases
Solution Approach 1:
The OPC server acts as an intermediary between the control devices and the OPC client. It monitors the operational status of multiple control devices, detects failures, and performs switchover automatically, eliminating the need for the OPC client to perform detection and selection operations. This intermediary role enables rapid switchover while maintaining redundant operation
Data Source
Figure 1
AI summary
The invention relates to a process control system (5) that has at least one OPC client (22) and an OPC server (30) which communicate via a standard OPC interface (31). The process control system (5) further has at least two redundantly operated control devices (40, 45), each of which communicates with the OPC server (30) via a coupling device (33, 34). Each control device is designed to provide process variables and status information. The status information includes the current role of the respective control device (40, 45), said current role being that of either a main control device or an auxiliary control device. The OPC server (30) is designed to detect the main control device (40) in response to the status information of at least one of the control devices, to register a variable list generated by the OPC client (22) at the main control device (40), and/or to merely transmit the process variables which have been provided by the main control device (40) to the OPC client (22).