Fieldbus Adapter Analog-Digital Signal Conversion

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Solution Overview

Problem

Existing fieldbus systems lack compatibility with analog control systems, preventing the incorporation of analog-type field devices into autonomous control systems.

Innovation Solution

A fieldbus adapter with a conversion unit that bidirectionally converts digital and analog signals, enabling the integration of analog-type field devices into autonomous control systems by using a protocol stack conforming to FOUNDATION fieldbus standards and supporting multiple device standards through function blocks and analog/digital conversion units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a fieldbus system uses digital signal protocols (FOUNDATION fieldbus, ISA 100.11a) to build an autonomous control system, then the system achieves higher automation and measurement/calculation functions, but existing analog control system resources cannot be incorporated due to lack of compatibility

Engineering Contradiction:
Improveautonomous control system capabilityVSAvoidcompatibility with analog control system resources
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The patent introduces a fieldbus adapter as an intermediary device that connects analog-type field devices to digital fieldbus systems. The adapter includes a conversion unit that bidirectionally converts digital signals from the fieldbus to analog signals for the field device, and vice versa. This mediator enables seamless integration of legacy analog resources into modern autonomous control systems without requiring replacement of existing analog devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conversion unit within the fieldbus adapter dynamically changes signal parameters by converting between digital signal formats (FOUNDATION fieldbus, ISA 100.11a, HART, BRAIN) and analog electrical signals (4-20mA). This parameter transformation allows the system to maintain compatibility across different signal types and protocols, enabling analog devices to participate in digital autonomous control architectures.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If analog-type field devices are directly connected to digital fieldbus systems, then signal compatibility is achieved, but the system loses the ability to incorporate existing analog control resources

Engineering Contradiction:
Improvesignal compatibilityVSAvoidincorporation of existing analog control resources
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The fieldbus adapter serves as a bridge that maintains signal compatibility while preserving the ability to incorporate existing analog control resources. The adapter's conversion unit translates signals between digital fieldbus protocols and analog electrical signals, allowing legacy analog devices to be integrated into modern digital control systems without loss of functionality or resource utilization.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If multiple fieldbus protocols (HART, FOUNDATION fieldbus, PROFIBUS, BRAIN, ISA100.11a) are supported, then system versatility is improved, but device complexity increases

Engineering Contradiction:
Improvemulti-protocol supportVSAvoidprotocol stack implementation
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fieldbus adapter is designed with universal multi-functionality to support multiple fieldbus protocols (FOUNDATION fieldbus, ISA 100.11a, HART, BRAIN, PROFIBUS) through a single device. The protocol stack in the adapter can be configured to handle different digital signal formats, and the conversion unit adapts to various analog signal types. This multi-functional design consolidates what would otherwise require multiple separate devices into one versatile adapter, managing complexity through integration rather than proliferation of components.

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

Data Source

PatentEP2551735B1Fieldbus adapter and method of using fieldbus adapter
Publication Date: 2019.08.21 YOKOGAWA ELECTRIC CORP
  • EP2551735B1 patent drawingFigure 1
  • EP2551735B1 patent drawingFigure 2~3
  • EP2551735B1 patent drawingFigure 4

AI summary

A fieldbus adapter (2) connected between a fieldbus (3) that handles a digital signal and a field device (1A-1D) that handles an analog signal, the fieldbus adapter (2) comprising a first connection unit (2b) detachably connected to the fieldbus (3), a second connection unit (2a) detachably connected to the field device (1A-1D), and a conversion unit (23) provided between the first connection unit (2b) and the second connection unit (2a), the conversion unit (23) bidirectionally converting the digital signal handled by the fieldbus (3) and the analog signal handled by the field device (1A-1D).