Capacitive Tapping of Voltage Signals in Multi-Core Cables
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Solution Overview
Problem
Existing methods for tapping communication signals in multi-core cables are limited, as they either require interrupting the signal line or can only detect current levels, failing to effectively reconstruct voltage signals.
Innovation Solution
A method using variable angular position electrodes for capacitive tapping, where multiple individual electrodes are allocated to collector electrodes via a controller or multiplexer to maximize the differential signal, allowing for the reconstruction of voltage signals without interrupting the line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamp-like tool is used to detect signals around the cable according to the transformer principle, then the signal line does not need to be interrupted, but only current levels can be detected and voltage signals cannot be effectively reconstructed
Solution Approach 1:
The patent replaces the transformer principle (magnetic field-based current detection) with capacitive coupling (electric field-based voltage detection). By using capacitive electrodes that couple to the signal line through the cable sheath, the system can detect voltage signals directly without relying on magnetic induction, thereby enabling effective reconstruction of voltage waveforms while maintaining contactless operation.
Solution Approach 2:
The patent introduces the cable sheath as an intermediary medium for capacitive coupling. Instead of directly contacting the signal line or relying on magnetic fields, the system uses the cable sheath as a capacitive interface between the external electrodes and the internal signal line, enabling non-invasive voltage signal extraction through the sheath.
2Measurement precision
If the cable sheath is removed to access the signal line for tapping, then voltage signals can be detected directly, but the cable integrity is compromised and reassembly is required
Solution Approach 1:
The patent uses the cable sheath as a capacitive intermediary, allowing voltage signal detection without removing or damaging the sheath. The capacitive coupling occurs through the sheath material itself, enabling direct voltage signal access while preserving cable integrity and eliminating complex reassembly procedures.
Solution Approach 2:
The patent replaces mechanical contact (requiring sheath removal and direct line contact) with electromagnetic capacitive coupling through the sheath. This substitution eliminates the need for physical access to the signal line while maintaining detection accuracy, significantly simplifying installation.
3Measurement precision
If multiple individual electrodes are used for capacitive tapping, then voltage signals can be reconstructed, but the device complexity increases due to the need for sequential electrode allocation
Solution Approach 1:
The patent employs dynamic switching of electrode allocations through a multiplexer, allowing the system to sequentially connect different individual electrodes to the measurement circuit. This dynamic reconfiguration enables the use of multiple electrodes for improved signal reconstruction while maintaining a compact device structure, as electrodes are activated in sequence rather than all simultaneously.
Solution Approach 2:
The patent uses a multiplexer to provide multiple functions from a single set of electrodes. The same physical electrodes can be allocated to different collector electrodes at different times, enabling the system to perform multiple measurement configurations with a single electrode array, thereby reducing overall device complexity.
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 the contactless tapping and reconstruction of voltage signals in multi-core cables, providing a reliable and non-invasive means to analyze communication signals without disrupting the signal line.
Implementation Method 1
the communication signals are tapped capacitively, wherein at least two electrodes are used for tapping which abut on the cable sheath
Implementation Method 2
the one angular position is determined at which the differential signal between the at least two collector electrodes is maximum
Data Source
AI summary
The invention relates to a method for the contactless tapping of communication signals that are exchanged between two communication units, in particular a sensor or actuator and a digital evaluating or control unit, wherein the communication signals are transmitted on a line (2) of a multi-core cable (1) as voltage signals. According to the invention, in order that the communication signals can be tapped also in the case of multi-core cables without the line having to be interrupted for this purpose, the communication signals are tapped capacitively, wherein at least two electrodes (10a, 10b), which lie on the cable sheath and the angular position of which in relation to the cable axis is variable, are used for the tapping and the angular position at which the differential signal between the two electrodes (10a, 10b) is maximized is determined, wherein the at least two electrodes (10a, 10b), each consisting of a plurality of individual electrodes (E1-E8), are designed as collection electrodes and the various angular positions of the collection electrodes (10a, 10b) are achieved in that the association of the individual electrodes (E1-E8) with the at least two collection electrodes (10a, 10b) is sequentially changed by means of a controller (26). The invention further relates to an assembly for performing said method.