Virtual PLC Reconstruction via Soft Guardian Monitoring
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Solution Overview
Problem
In PLC-based distributed control systems, the failure of multiple hard PLCs in one area can lead to the entire system being shut down, as there is no efficient method to reconstruct or redeploy virtual PLCs without powering off servers and reconnecting them, disrupting normal operations.
Innovation Solution
A method and apparatus for monitoring and reconstructing software-defined PLCs using a server cluster with multiple micro kernels and soft guardians, allowing for the reconstruction of virtual PLCs on a target micro kernel without powering off servers, utilizing virtualized real-time operating systems and soft guardians to maintain system uptime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple hard PLCs and their redundant PLCs fail in one area, then the system switches to redundant PLCs, but the entire distributed control system must be stopped to replace the failed hard PLCs
Solution Approach 1:
The patent segments the PLC system into multiple independent areas, each with its own control domain. When PLCs fail in one area, only that area is affected while other areas continue operating independently. This is achieved by dividing the distributed control system into area-specific control units with localized redundancy.
Solution Approach 2:
The patent creates virtual copies of PLC functionality through virtualization technology. Virtual PLCs can be rapidly instantiated on available hardware platforms, providing immediate backup capacity without requiring physical replacement of failed components. This allows hot-swapping of PLC functions across different physical hosts.
2Ease of repair
If hard PLCs are replaced in the failing area, then the failed PLCs are restored, but the entire distributed control system must be powered off for reconnection
Solution Approach 1:
The patent enables continuous operation of the distributed control system during PLC repairs by maintaining active control in unaffected areas. The system continues executing control tasks in healthy regions while failed components are replaced, eliminating the need for complete system shutdown and minimizing overall downtime.
Solution Approach 2:
The patent introduces a virtualization layer as an intermediary between physical PLC hardware and control functions. This abstraction layer allows seamless migration of control tasks between physical hosts, enabling hardware replacement without interrupting the control logic or requiring system-wide reconnections.
3Productivity
If virtual PLCs are reconstructed on target micro kernels, then rapid reconstruction is achieved, but multiple micro kernels and soft guardians must be deployed on each physical core
Solution Approach 1:
The patent makes each physical core universal by deploying multiple micro kernels on it, allowing any micro kernel to host any virtual PLC. This multi-functionality enables flexible resource allocation and rapid reconstruction of virtual PLCs on alternative micro kernels when failures occur, without being constrained to one-to-one mapping.
Solution Approach 2:
The patent implements a nested architecture where virtual PLCs are contained within micro kernels, which are in turn hosted on physical cores. This nested structure allows virtual PLCs to be independently managed and migrated within the micro kernel layer, enabling rapid reconstruction by relocating virtual instances between nested micro kernel containers.
Data Source
AI summary
Method and apparatus for monitoring and reconstructing a software-defined PLC are provided. The method includes: upon monitoring a PLC fails, obtaining, by a soft guardian, an operating state of each physical core on each server in a server cluster, and an operating state of each micro kernel on the each physical core; determining a target micro kernel according to the operating state of each physical core on each server, and the operating state of each micro kernel on each physical core; and transmitting a reconstruction instruction to the target micro kernel to instruct the virtual PLC to be reconstructed on the target micro kernel.