Field Equipment Loop Cable Resistance Mapping by Unit Activation

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Solution Overview

Problem

Existing methods for diagnosing field equipment loop cables struggle to accurately measure resistance within individual segments and branching pathways, leading to potential device malfunctions and compromised system reliability due to elevated resistance and voltage drops.

Innovation Solution

A diagnostic device and method that utilizes a loop driver with current limiters and sensors to selectively activate loop units, measure resistance, and map resistance values to specific locations, enabling precise identification of weak points in the cable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing diagnostic methods are used for loop cables, then the diagnostic process is simple, but the measurement precision of resistance within individual segments and branching pathways is insufficient

Engineering Contradiction:
Improveresistance measurement precisionVSAvoiddiagnostic device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The diagnostic device segments the loop cable into multiple measurement segments by selectively activating specific loop units through switch control. Each segment can be measured independently by controlling the switch state, allowing precise resistance measurement of individual cable sections and branching pathways without measuring the entire loop at once.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device uses controllable switches that can dynamically change their state between connected and disconnected. This dynamic switching capability allows the measurement circuit to be reconfigured for different measurement segments, enabling the same hardware to measure multiple different cable segments by changing the electrical connection topology.

Inventive Principle:
Principle #15Dynamics

2Reliability

If existing diagnostic methods are used, then the device complexity is low, but system reliability is compromised due to inability to detect elevated resistance and voltage drops

Engineering Contradiction:
Improvesystem reliabilityVSAvoiddiagnostic device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The diagnostic device incorporates voltage sensors that continuously monitor voltage levels at different points in the loop cable. By comparing measured voltage values against expected values, the system can detect voltage drops caused by elevated resistance. This feedback mechanism enables automatic identification of problematic cable segments, improving system reliability through continuous monitoring and fault detection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The device replaces manual diagnostic methods with automated electrical measurement and control systems. Instead of physical inspection or simple continuity testing, the system uses electronic sensors, controllable switches, and automated measurement circuits to detect resistance issues and voltage drops, providing more reliable and precise diagnostics.

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

3Measurement precision

If selective activation of loop units is implemented, then resistance of individual segments can be determined, but the operation complexity increases

Engineering Contradiction:
Improvesegment resistance measurement precisionVSAvoidoperational simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The diagnostic device automatically controls the switching sequence and measurement process without requiring manual intervention for each measurement step. The controller autonomously activates specific loop units, performs resistance measurements on selected segments, and processes the results, reducing operational complexity despite the sophisticated measurement capabilities.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The device performs measurements in a systematic periodic sequence, cycling through different loop unit activation patterns and measurement configurations. This structured periodic operation simplifies the user interface by presenting a unified diagnostic process that automatically progresses through all necessary measurements without requiring the operator to manually configure each measurement parameter.

Inventive Principle:
Principle #19Periodic action

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 precise determination of resistance within cable segments and branches, facilitating proactive maintenance and ensuring the reliability and safety of field equipment systems by identifying and addressing potential faults before they escalate.

Implementation Method 1

one or more current limiters to supply and regulate the flow of current through the cable and the respective loop units

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

one or more electrical sensors to monitor the current flowing through the cable and monitor the voltage at the corresponding positive terminal and the negative terminal

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 3

determine resistance between the one or more loop driver and the activated loop unit based on the monitored voltage, and the monitored current

Methodology Applied
Scientific EffectOhm's Law: Ohm's Law

Data Source

PatentEP4628906A1Device and method for diagnosing field equipment loop cable
Publication Date: 2025.10.08 CARRIER CORP
  • EP4628906A1 patent drawingFigure 1A
  • EP4628906A1 patent drawingFigure 1B
  • EP4628906A1 patent drawingFigure 1C

AI summary

Described herein is a device for diagnosing a field equipment loop cable connected to a plurality of loop units. The device comprises one or more loop driver configured to be connected to one or more ends of the cable. The one or more loop driver comprises current limiter, electrical sensors, and a controller. The controller is configured to selectively activate one of the loop units while electrically isolating the remaining loop units, actuate the current limiter to supply and regulate flow of the current through the activated loop unit to a predetermined level, monitor, using the electrical sensors, the current flowing through cable via the activated loop unit and the voltage at the positive terminal and the negative terminal of the cable, and determine resistance between the loop driver and the activated loop unit based on the monitored voltage and current.