Field Interface Auto-Detection for Analog and Digital Signal Switching

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Solution Overview

Problem

Field devices in process automation often face misinterpretation of signals due to incorrect configuration of transmission standards, leading to potential hazards like overheating or overfilling, as they need to switch between analog and digital signal transmission standards without manual reconfiguration.

Innovation Solution

A field device with a secure interface featuring two current regulators and a control unit that automatically detects the connection type and adjusts the transmission standard, allowing for redundant checking of contact configurations and enabling automatic reconfiguration without manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the field device uses a multi-pole interface for signal transmission, then the device can support multiple transmission standards (analog and digital), but the risk of misinterpretation of measured values increases due to incorrect configuration

Engineering Contradiction:
Improvetransmission standard compatibilityVSAvoidsignal interpretation accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The field device performs preliminary detection of the connected transmission standard before actual measurement data transmission. The control unit detects whether a digital or analog standard is connected via the multi-pole interface, and only after successful detection and confirmation does it transmit measurement data. This preliminary action prevents misinterpretation by ensuring the correct transmission standard is identified before data exchange occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit continuously monitors the interface connections and provides feedback about the detected transmission standard. When a change in connection is detected, the control unit re-detects the standard and adjusts its transmission mode accordingly. This feedback mechanism ensures that the field device adapts to the correct transmission standard, maintaining reliable signal interpretation even in dynamically changing connection scenarios.

Inventive Principle:
Principle #23Feedback

2Reliability

If manual reconfiguration is required when rewiring the field device, then the transmission standard can be correctly set, but the complexity of operation increases and safety risks remain during the configuration process

Engineering Contradiction:
Improvetransmission standard configurationVSAvoidreconfiguration process
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The field device performs self-configuration by automatically detecting the connected transmission standard through its control unit. When rewired or reconnected, the field device autonomously identifies whether a digital or analog standard is present and configures its transmission mode accordingly, without requiring manual intervention. This self-service capability eliminates configuration errors and simplifies operation while maintaining reliable signal transmission.

Inventive Principle:
Principle #25Self-service

3Reliability

If the field device continuously monitors connection changes, then the transmission standard can be automatically adjusted, but the energy consumption increases

Engineering Contradiction:
Improveconnection detection accuracyVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit performs connection detection periodically rather than continuously. It monitors for changes in the transmission standard at predetermined intervals or upon detecting specific change events, such as connection establishment or disconnection. This periodic monitoring approach maintains reliable connection detection accuracy while significantly reducing energy consumption compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4031944B1Field device
Publication Date: 2023.10.04 ENDRESS & HAUSER GMBH & CO KG
  • EP4031944B1 patent drawingFigure 1
  • EP4031944B1 patent drawingFigure 2
  • EP4031944B1 patent drawingFigure 3

AI summary

The invention relates to a field device (1) comprising a secure interface (11), and a corresponding method for operating said field device (1). The field device is based on two current controllers (12, 13) which are designed to adjust a respective current (a1, a2) between corresponding contacts (111-114) of the interface (11). In this way, the field device (1) checks which of said contacts (111-114) is connecting the field device (1) to the higher-level unit (4), such that an automatic configuration of the interface (11) can be carried out at the corresponding transmission standard. With the contacting with the higher-level unit (4) being checked by two current controllers (12, 13) and in a cyclically repeating manner, it is ensured that the field device (1) can even determine a change in the contacting with the interface (11) during the measuring operation and automatically react. This makes the interface (11) secure and thereby increases the security of the processing system in which the field device (1) is installed.