Redundant Flow Control for Deterministic Time-Critical Applications
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Solution Overview
Problem
Industrial automation systems without real-time capabilities struggle to execute time-critical control applications due to the lack of direct access to hardware and potential delays in executing high-priority control applications.
Innovation Solution
The system employs mutually redundant sequence control components executed in parallel, which capture measurement and/or state variables to determine manipulated variables for processes. These components transmit the variables via data streams with sequence numbers, ensuring deterministic and redundant transmission, even in environments without real-time extensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control applications are executed in virtualized control systems or operating systems without real-time extensions, then system flexibility and ease of operation are improved, but deterministic execution sequence and real-time performance deteriorate
Solution Approach 1:
The system performs preliminary actions by capturing measurement and state variables at predetermined capture times before control calculations are executed. This pre-capturing ensures that data is ready when needed, maintaining deterministic timing even in virtualized environments where execution schedules can vary.
Solution Approach 2:
The invention uses sequence numbers to create logical copies of control cycles, allowing the system to track and manage multiple control applications independently. Each control application receives data with sequence numbers that correspond to its specific capture times, enabling deterministic behavior through logical replication rather than physical hardware timing.
2Adaptability or versatility
If multiple control applications simultaneously require exclusive access to the same resource in a virtualized environment, then application versatility is improved, but execution timing and real-time performance deteriorate
Solution Approach 1:
The system segments the control execution into distinct capture phases and calculation phases for different control applications. By dividing the control cycle into separate segments with dedicated capture times for each application, the system allows multiple applications to access shared resources without mutual interference, maintaining timing precision while supporting versatility.
Solution Approach 2:
The invention dynamically assigns capture times and sequence numbers to different control applications based on their specific requirements. This dynamic allocation allows the system to adapt resource access timing for each application while maintaining overall deterministic behavior, resolving the conflict between versatility and timing precision.
3Device complexity
If conventional IT infrastructure is used instead of real-time systems, then system complexity and cost are reduced, but real-time control capability and deterministic performance deteriorate
Solution Approach 1:
The system introduces sequence numbers as an intermediary mechanism between conventional IT infrastructure and deterministic control requirements. These sequence numbers act as a mediator that allows standard computing hardware to track and enforce deterministic execution sequences without requiring specialized real-time hardware, bridging the gap between complexity reduction and performance maintenance.
Solution Approach 2:
The invention changes the parameter of time tracking from hardware-based real-time clocks to software-based sequence number counters. This parameter change allows conventional IT infrastructure to provide deterministic control capability by using software mechanisms rather than specialized hardware, reducing system complexity while maintaining reliability.
Data Source
AI summary
System and method for providing time-critical control applications via flow control components that are each loadable into and executable by a flow control environment formed via a server device, wherein the control applications each periodically determine, from periodically acquired measured and/or state variables, manipulated variables for a process to be controlled or regulated, a plurality of mutually redundant flow control components are executed in parallel with one another, the mutually redundant flow control components determine the manipulated variables for a respective process cycle that follows a respective acquisition time of the measured and/or state variables when a majority of the mutually redundant flow control components signal error-free presence of the measured and/or state variables for the respective acquisition time, where as an alternative or in addition, the determined manipulated variables are transmitted, together with a sequence number assigned to the respective process cycle, to actuators and/or control units.