Ladder Diagram Circuit Replacement for Readable PLC Logic

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Solution Overview

Problem

As ladder diagram programs scale, repeated partial circuits increase complexity, reducing readability and debugging efficiency due to their composition of multiple contacts.

Innovation Solution

A device that selects and replaces repeated partial circuits with fewer contacts, inserting auxiliary circuits to maintain functionality, thereby improving readability and debugging efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the same partial circuit is repeatedly used in a ladder diagram program, then the program functionality is maintained, but the program complexity increases and readability decreases

Engineering Contradiction:
Improveprogram functionalityVSAvoidprogram complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the ladder diagram program into distinct circuit blocks. Each repeated partial circuit is identified and extracted as a separate block that can be independently managed and referenced multiple times, reducing overall program complexity while maintaining functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universality by creating reusable circuit blocks that can be instantiated multiple times throughout the program. A single block definition serves multiple functions by being referenced in different locations, reducing redundancy and improving readability without sacrificing program functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the same partial circuit is repeatedly used in a ladder diagram program, then the program functionality is maintained, but debugging efficiency is reduced

Engineering Contradiction:
Improveprogram functionalityVSAvoiddebugging efficiency
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

By segmenting the program into distinct circuit blocks, the patent enables independent debugging of each block. Problems can be isolated to specific blocks rather than searching through repeated instances of partial circuits, significantly improving debugging efficiency while maintaining program functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms that allow operators to monitor and debug circuit blocks independently. When a block is executed multiple times, the system provides feedback about each instance's execution status, enabling efficient identification and resolution of issues without affecting other parts of the program.

Inventive Principle:
Principle #23Feedback

3Reliability

If multiple contacts are used in a partial circuit, then the circuit functionality is achieved, but the number of contacts increases complexity

Engineering Contradiction:
Improvecircuit functionalityVSAvoidnumber of contacts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining multiple contacts into a single circuit block. Instead of displaying and managing each contact individually across multiple instances, the contacts are merged into a unified block that can be referenced repeatedly, reducing the apparent complexity while maintaining the underlying circuit functionality.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3940472B1Ladder diagram program creation assistance device, ladder diagram program creation assistance method, and ladder diagram program creation assistance program
Publication Date: 2024.03.13 OMRON CORP
  • EP3940472B1 patent drawingFigure 1
  • EP3940472B1 patent drawingFigure 2
  • EP3940472B1 patent drawingFigure 3

AI summary

A partial circuit selection unit selects a partial circuit comprising a plurality of contacts in a ladder diagram program. A replacement circuit generation unit generates a replacement circuit comprising a smaller number of contacts than in the selected partial circuit. An auxiliary circuit generation unit generates an auxiliary circuit that causes the replacement circuit to perform the same action as the partial circuit. A program editing unit performs, on the ladder diagram program, a replacement process for replacing a partial circuit appearing in the ladder diagram program with the replacement circuit, and performs an auxiliary circuit insertion process for inserting the auxiliary circuit into the ladder diagram program.