PLC Program Variable Attribute Checking for Reusable Control Logic

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Solution Overview

Problem

Existing techniques fail to effectively improve design efficiency and reusability of user programs executed by control devices like PLCs, particularly in handling variables with different reference attributes across multiple programs.

Innovation Solution

A program development device that sets and evaluates attributes for variables used in user programs, ensuring consistency based on predefined attributes for IO and inter-program references, allowing for modularized reuse and presentation of evaluation results to enhance design efficiency and reusability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If variable reference attributes are not evaluated across multiple programs, then program development is simpler and faster, but program reusability and consistency deteriorate

Engineering Contradiction:

Improveprogram development efficiencyVSAvoidprogram reusability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by evaluating variable reference attributes during the program development phase before the program is executed or deployed. The consistency evaluation means analyzes variable attributes (such as I/O signal references, global variables, local variables) in advance to determine whether variables are properly referenced across multiple programs. This preliminary evaluation ensures program reusability and consistency is established before actual use, preventing errors that would otherwise manifest during runtime or maintenance phases.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If attribute setting and consistency evaluation are implemented for all variables, then program consistency and reusability improve, but device complexity and development time increase

Engineering Contradiction:

Improveprogram consistencyVSAvoiddevelopment system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by implementing attribute setting and consistency evaluation specifically for variables that have reference attributes, rather than uniformly processing all program elements. The evaluation means focuses on variables with specific attributes (I/O signal references, global variables, local variables) and their reference relationships. This targeted approach ensures program consistency for critical variables while avoiding unnecessary complexity for variables that do not require such evaluation, thus balancing reliability improvement with manageable system complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary consistency evaluation means that acts as a mediator between variable definition and program execution. This evaluation means analyzes variable reference attributes and generates consistency evaluation results without requiring direct modification of the control device or execution environment. The intermediary nature of this evaluation system allows complexity to be isolated in the development tool rather than propagated to the running system, maintaining program consistency while managing overall system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If manual variable reference checking is performed, then flexibility and adaptability are maintained, but time consumption and human error increase

Engineering Contradiction:

Improveprogram adaptabilityVSAvoidvariable checking time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies self-service by implementing automatic consistency evaluation that performs variable reference checking without requiring manual intervention. The evaluation means automatically analyzes variable attributes, traces reference relationships across programs, and generates consistency evaluation results. This automated self-service approach maintains program adaptability through configurable evaluation rules while eliminating the time consumption and human error associated with manual variable reference checking.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements feedback by having the consistency evaluation means generate evaluation results that provide information about variable reference consistency. This feedback mechanism allows developers to identify and correct inconsistent variable references, ensuring program adaptability is maintained while reducing time consumption through automated detection rather than manual checking. The feedback loop enables continuous improvement of program consistency without proportionally increasing development time.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12259804B2Program development device, and program for providing program development device

Publication Date: 2025.03.25 OMRON CORP

AI summary

A program development device provides a development environment of a user program executed by a control device. The program development device receives setting of an attribute related to reference from a program for each of one or more variables used in the user program including a first program and a second program having a calling relationship. The set attribute includes a first attribute referred to by any one of the first program and the second program and a second attribute referred to by both the first program and the second program. The program development device analyzes the user program and evaluates consistency based on the set attribute related to reference from the program for each of the one or more variables.