Passive Termination for Two-Wire Line Resistance Monitoring

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Solution Overview

Problem

Existing fire protection systems struggle to accurately determine both series and parallel resistances in two-wire lines, often requiring complex active termination components or failing to differentiate between them, which can lead to inadequate voltage for device triggering or short circuits.

Innovation Solution

A device with a passive terminating component, including a chargeable energy store and constant current source, allows for the separate determination of series and parallel resistances by analyzing voltage curves during and after the measurement current is applied, using a control unit to evaluate the voltage profile and determine resistances without the need for complex calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If active termination components are used to monitor two-wire lines, then measurement capability is improved, but device complexity and maintenance requirements increase

Engineering Contradiction:
Improveresistance measurement capabilityVSAvoidtermination component complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex active termination components with simple passive resistors that can be easily installed and replaced. These passive components perform the necessary termination function without requiring power supplies, controllers, or complex circuitry, thereby reducing device complexity while maintaining measurement capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the termination function from complex active components and implements it using simple passive resistors connected in parallel with the two-wire line. This separation allows the termination function to be performed independently without requiring additional active elements, reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If passive termination components are used, then device complexity is reduced, but temperature influences from semiconductor components affect performance

Engineering Contradiction:
Improvetermination component simplicityVSAvoidtemperature influence on resistance
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent uses simple passive resistors that are less sensitive to temperature variations compared to active semiconductor-based components. These passive components provide stable termination values across a range of temperatures without requiring complex compensation mechanisms.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If only one resistance value is measured, then measurement simplicity is maintained, but the ability to detect specific faults is reduced

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidfault detection capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the resistance measurement into two independent measurements: one for the series resistance (longitudinal resistance) and one for the parallel resistance (inter-wire resistance). By measuring these separately using different test configurations, the system can detect specific faults more accurately while maintaining operational simplicity through automated measurement sequences.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a temporal dimension to the measurement process by performing measurements at different times or in different sequences. This allows the system to measure series and parallel resistances separately without requiring complex simultaneous measurement setups, thereby maintaining simplicity while improving fault detection capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 accurate and efficient determination of series and parallel resistances, ensuring sufficient voltage for device triggering while preventing short circuits, without the need for expensive active termination components or temperature-dependent passive components.

Implementation Method 1

the passive termination component has a rechargeable energy storage device

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a constant current source for providing a measuring current to the passive termination component

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3797408B1Device, method, and control module for monitoring a two-wire line
Publication Date: 2022.07.06 MINIMAX GMBH & CO KG
  • EP3797408B1 patent drawingFigure 1
  • EP3797408B1 patent drawingFigure 2
  • EP3797408B1 patent drawing

AI summary

The invention relates to a device (1) and a corresponding method for monitoring a two-wire line (2), in particular a two-wire line (2) of a fire protection system. The device (1) comprises a passive closure component (10) for closing the two-wire line (2), said passive closure component having a chargeable energy store (12), a constant power source (20) for providing a measurement current (I1) to the passive closure component, a voltage detection unit (30) for detecting a voltage curve (V1) at an output terminal (4, 6) of the two-wire line (2), and a control unit (40) for actuating the constant power source (12) and for analyzing the detected voltage curve, wherein the control unit (40) is designed to determine the series resistance (RL) and the parallel resistance (PS) of the two-wire line (2).