Mains Synchronization Circuit for Magnetic-Inductive Flowmeters

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Solution Overview

Problem

Remote magneto-inductive flowmeters face challenges in jitter-free transmission of synchronization signals over long distances, requiring additional cables and susceptible to interference.

Innovation Solution

A method that generates a differential synchronization signal on the power supply side, modulates it onto a DC signal transmitted via two signal conductors, and separates it at the sensor side for processing, eliminating the need for extra cables and minimizing jitter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate cable is used to transmit the synchronization signal from the transmitter to the remote sensor, then the synchronization signal can be transmitted independently, but the device complexity and installation cost increase

Engineering Contradiction:

Improvesynchronization signal transmissionVSAvoidcable structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the power supply function and synchronization signal transmission function into a single cable system. The power supply cable simultaneously carries both the DC power signal and the AC synchronization signal, eliminating the need for separate synchronization cables and reducing overall system complexity while maintaining reliable signal transmission to remote sensors

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The power supply cable is designed to serve multiple functions: it provides both electrical power (DC signal) and synchronization timing (AC signal) to the remote sensor. This multi-functional approach allows a single cable to replace what would traditionally require two separate cables, simplifying installation and reducing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the synchronization signal is transmitted over long distances via cable, then remote sensors can be synchronized, but signal jitter and interference increase

Engineering Contradiction:

Improveremote sensor synchronizationVSAvoidsignal quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent converts the potential harm of cable capacitance and interference into a benefit by using differential signaling. The synchronized AC signal is transmitted as a differential voltage superimposed on the power supply lines, and the sensor uses the difference between the two lines to reject common-mode noise and interference, thereby maintaining signal quality over long distances

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces an intermediary approach by modulating the synchronization signal onto the power supply cable in a differential manner. Rather than transmitting the synchronization signal directly, it uses the power cable as an intermediary medium, encoding the sync information in the differential voltage between the power lines, which naturally rejects electromagnetic interference

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If additional cables are installed for synchronization signal transmission, then signal interference is reduced, but installation cost and complexity increase

Engineering Contradiction:

Improvesignal interferenceVSAvoidinstallation process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges the power supply function and synchronization signal transmission into a single cable system. The power supply cable simultaneously carries both the DC power signal and the AC synchronization signal, eliminating the need for separate synchronization cables and reducing overall system complexity while maintaining reliable signal transmission to remote sensors

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2788725B1Method and circuit for the mains synchronisation of a magnetic-inductive flow measurement device

Publication Date: 2019.09.18 ENDRESS HAUSER FLOWTEC AG

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AI summary

Circuit and method for the mains synchronisation of a magnetic-inductive flow measurement device having a transducer and a mains adapter, wherein a direct current signal for the supply of the transducer is transmitted from the mains adapter to the transducer via two signal conductors, characterised by the following process steps: mains-adapter-side generation of a differential synchronisation signal for the synchronisation of the flow measurement with the mains frequency; transmission of the differential synchronisation signal via the two signal conductors to the transducer; transducer-side separation of the differential synchronisation signal and the direct current signal; processing of the differential synchronisation signal for the synchronisation of the flow measurement with the mains frequency.