PLC Program Copy Comparison Using Merged Graphical Views
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Solution Overview
Problem
Existing methods for displaying discrepancies between a user program for a programmable logic controller and its copy are tedious and error-prone, failing to reliably recognize accidental falsifications or errors that may occur during transmission or in the insecure workstation computer environment.
Innovation Solution
A method that generates graphical representations of both the user program and its copy using a representation model, applies a merging algorithm to highlight discrepancies, and displays the merged representation on the workstation computer, allowing for immediate recognition of errors by comparing pixel-by-pixel and enhancing visibility through color manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diverse representations of the user program are used (e.g., function block diagram and textual command lines), then the user can detect potential corruptions, but the verification process becomes tedious and error-prone
Solution Approach 1:
The patent merges multiple representations (function block diagram and textual command lines) into a single unified graphical display. The merging algorithm automatically compares the two representations and integrates them, allowing the user to view both formats simultaneously in one graphical interface rather than having to manually correlate separate displays. This resolves the contradiction by maintaining the reliability benefit of diverse representations while eliminating the tedious manual verification process.
2Reliability
If a separate verification step is implemented to check the application program, then program integrity can be ensured, but the programming process becomes cumbersome and time-consuming
Solution Approach 1:
The patent performs the verification action preliminarily by continuously comparing the function block diagram and textual command lines in the background during the programming process. The merging algorithm automatically detects discrepancies between the two representations without requiring the user to initiate a separate verification step. This resolves the contradiction by ensuring program integrity through automatic comparison while eliminating the time loss associated with manual verification steps.
3Measurement precision
If the user manually correlates the function block diagram with textual command lines to check for discrepancies, then potential errors can be identified, but the process is tedious and often not carried out with necessary care
Solution Approach 1:
The patent implements self-service by enabling the system to automatically perform the comparison and discrepancy detection that would otherwise require manual user action. The merging algorithm autonomously correlates the function block diagram and textual command lines, identifies discrepancies, and presents them to the user in the unified graphical display. This resolves the contradiction by maintaining high error detection accuracy through automatic comparison while eliminating the complexity and user burden of manual verification procedures.
Data Source
Figure 1
Figure 2a~2b
AI summary
In a method for displaying discrepancies between a user program for a programmable logic controller (PLC) and its copy, wherein the program is stored on a workstation for editing using an editor and the program copy is stored in a memory of the PLC, wherein a graphical representation of the user program is created using a representation model, a graphical representation of the program copy is also created using the representation model, wherein the graphical representation of the user program and the graphical representation of the program copy are subjected to a merging algorithm that produces a merged graphical representation,which is supplied to a display device assigned to the workstation computer for display purposes and which makes any discrepancies between the graphical representation of the user program and the graphical representation of the program copy apparent in the graphical display.