OPC-UA Controller Memory Restriction for Continuous Machine Control
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Solution Overview
Problem
Factory automation systems face significant opportunity loss when memory usage exceeds thresholds, causing the entire system to stop, and existing solutions fail to restrict server functions without affecting driving machines.
Innovation Solution
A control device with a server section that monitors memory usage and restricts server functions when thresholds are exceeded, allowing the execution of control programs for driving machines to continue while reducing memory usage and logging restrictions for external storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller stops all functions to deny external access requests when memory usage is high, then external access is restricted, but the FA system stops causing significant opportunity loss
Solution Approach 1:
The patent segments the controller's functions into two independent parts: the server function for external access and the control program execution for driving machines. When memory usage exceeds the first threshold, only the server function is restricted while the control program execution continues independently. This segmentation allows external access to be limited without stopping the entire FA system, thus resolving the contradiction between external access reliability and FA system productivity.
2Adaptability or versatility
If the controller uses a portion of memory for server function to handle external access requests, then external communication capability is improved, but memory usage increases beyond intended levels
Solution Approach 1:
The patent implements a feedback mechanism where the monitoring section continuously monitors memory usage and provides information to the restriction section. When memory usage exceeds the first threshold, the restriction section activates to limit the server function, thereby reducing memory consumption. This feedback loop ensures that external communication capability is maintained within acceptable memory usage limits, resolving the contradiction between adaptability and quantity of substance.
3Ease of operation
If the controller maintains full server function to handle external requests, then external access performance is improved, but memory usage exceeds thresholds causing system stop
Solution Approach 1:
The patent introduces dynamic adjustment of server function based on memory usage conditions. The restriction section dynamically limits the server function when memory usage exceeds the first threshold and restores it when below the second threshold. This dynamic behavior allows the system to maintain external access performance under normal conditions while preventing system stop under high memory usage, resolving the contradiction between ease of operation and reliability.
Data Source
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AI summary
There is expected a technique for restricting a server function without affecting a driving machine in the case where memory usage is increased. A controller (100) includes a memory (106), a program execution section (103) controlling a driving machine (200) in accordance with a control program (112), and an OPC-UA server (150) communicating with an external machine (300). The OPC-UA server (150) includes: a function execution section (152), executing a function utilizing a memory region on the memory (106) in response to a request from the external machine (300); a monitoring section (154) monitoring usage of the memory (106); and a restriction section (156), stopping the above function of the OPC-UA server (150) based on the fact that the usage has exceeded a predetermined threshold.