Capacitive Cable Harness Testing for Open-End Wire Detection

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Solution Overview

Problem

Conventional cable harness testers require plug connections on both sides of wires, making it time-consuming and labor-intensive to test cable harnesses with open wires, especially those with connectors on only one side, as they need to contact individual wires for testing.

Innovation Solution

A method and device that use capacitive sensing to detect the presence of wires within a cable harness by applying a test signal and measuring the electrical potential, allowing for contactless line detection and identification of shielded cables, without the need for physical contact with the second ends of the wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional cable harness testers are used to test cable harnesses with open wires, then individual wire contact is achieved, but testing time and labor effort increase significantly

Engineering Contradiction:
Improvewire detection accuracyVSAvoidtesting speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical contact-based testing system with a capacitive sensing system. Instead of physically contacting each wire with test probes, the system uses an electrode that forms capacitors with wires through non-contact or minimal-contact means, enabling simultaneous detection of multiple wires and dramatically reducing testing time while maintaining detection accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If plug connections are required on both sides of wires for testing, then contact resistance measurement is enabled, but device complexity and handling effort increase

Engineering Contradiction:
Improveconnection completenessVSAvoidtester configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the requirement for dual-side plug connections and replaces it with a single-side electrode placement approach. The capacitive sensing method only requires the electrode to be placed on one side of the cable harness, forming capacitors with wires that pass through or near the electrode, thereby simplifying the testing setup while still enabling reliable wire detection and connection verification

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrode serves multiple functions: it forms capacitors with multiple wires simultaneously, enables detection of both shielded and non-shielded cables, and provides a universal testing interface that works with different cable harness configurations without requiring separate test setups for each type

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

3Measurement precision

If individual wire contact is performed for testing, then precise wire identification is achieved, but testing effort and time consumption increase

Engineering Contradiction:
Improvewire identification accuracyVSAvoidtesting duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the detection of multiple wires into a single capacitive sensing operation. By placing one electrode that can form capacitors with multiple wires simultaneously, the system combines what would otherwise require multiple separate contact measurements into a single unified testing step, maintaining wire identification accuracy while reducing testing duration

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient and rapid testing of cable harnesses with open ends by determining the presence of all lines in a bundle, reducing testing time and effort, and effectively identifying both individual wires and shielded cables without the need for extensive handling or additional connections.

Implementation Method 1

An electrode (16) is placed on a test section (18). The arrangement is such that the electrode forms a respective capacitor with each of the lines (4) of the line bundle (20) in the test section (18)

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3505945B1Method and measuring device for checking a cable harness
Publication Date: 2023.06.07 ESPI LOGISTICS
  • EP3505945B1 patent drawingFigure 1
  • EP3505945B1 patent drawingFigure 2
  • EP3505945B1 patent drawingFigure 3a~3b

AI summary

In a method for checking a cable harness (2), a test section (18) of the cable harness (2) with at least one conductor (4a-f) is selected, an electrode (16) is arranged on the test section (18) which forms capacitors (Ca-c) with the conductors (4a-c), a test lead is selected and a test signal (P) is applied, a reference potential (R) is applied to all other conductors, a characteristic value (K) is determined on the basis of the electrical potential (M) of the electrode (16), and a decision (E) is made as to whether the test lead is located in the test section (18) if the characteristic value (K) fulfills a test criterion (T), or not.A measuring device (12) for checking the cable harness (2) with a plurality of coupling elements (14a-f) for contacting the lines (4a-f) includes the electrode (16) and a control and evaluation unit (22) which is connected to the coupling elements (14a-f) in order to selectively provide the test signal (P) or the reference potential (R) there, and which is connected to the electrode (16), and which carries out the method according to the invention, and which has an output interface (24) for the decision (E).