PLC Log Saving With Program Version Association
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Solution Overview
Problem
In the field of programmable logic controllers (PLCs), there is a challenge in maintaining consistency between project data used by the PLC and project data held in the program creation supporting apparatus, leading to inconsistencies when revising user programs, as the version of project data on the PLC may differ from the version referred to by the monitor software, making it difficult to accurately associate log data with the correct project data.
Innovation Solution
The solution involves a system configuration that includes a program storing section, a program executing section, a device storing section, and a saving section, which records device values in a time series and saves them in correspondence with the user program or its identification information, allowing for easy specification of the relationship between log data and project data by outputting both alongside identification information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PLC executes a user program and generates log data, then the control function is achieved, but inconsistency arises between the project data on the PLC and the project data in the program creation supporting apparatus, making it difficult to accurately associate log data with the correct program version
Solution Approach 1:
The patent applies preliminary action by embedding version identification information into the user program itself before execution. The PLC reads this embedded identification information and uses it to accurately associate log data with the corresponding program version, eliminating the need for complex external version management systems.
Solution Approach 2:
The patent introduces version identification information as an intermediary element that bridges the log data and the user program. This identification information, embedded within the program, serves as a mediator that enables accurate association without requiring complex matching mechanisms between separate data stores.
2Ease of operation
If the monitor software displays log data and project data in parallel to assist program revision, then ease of operation is improved, but incorrect information is displayed when version inconsistency exists between PLC project data and monitor software project data
Solution Approach 1:
The monitor software reads the version identification information embedded in the user program on the PLC before displaying log data. By performing this version identification in advance, the software ensures that only log data corresponding to the currently displayed program version is shown, preventing information mismatch while maintaining ease of operation.
Solution Approach 2:
The system implements feedback by using the version identification information to dynamically control which log data is displayed in the monitor software. This feedback mechanism ensures that the displayed information always corresponds to the correct program version, maintaining measurement precision while preserving ease of operation.
3Reliability
If version identification information is embedded in the user program and used by the PLC to save log data in association with the program, then reliability of data association is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent merges the version identification information directly into the user program structure. By combining these elements, the system reduces processing complexity because the identification information is already available within the program itself, eliminating the need for separate version tracking systems while maintaining reliable log data association.
Data Source
AI summary
A PLC includes a program storing section which stores a user program, a program executing section which repeatedly executes the user program, a device storing section having a plurality of devices which are memory regions referred to by the program executing section, a device recording section which records a device value stored in any one of the plurality of devices in time series, and a saving section which saves, when a predetermined saving condition is satisfied, the device value recorded by the device recording section and the user program or identification information of the user program stored in the program storing section in correspondence with each other in a memory.