Field Device Master-Slave Inversion for Secure Message Timing

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Solution Overview

Problem

Existing systems face challenges such as insufficient resources for processing messages within tight time frames, unsolicited messages from control devices posing security risks, and uncertainty about message transmission times.

Innovation Solution

By reversing the master and slave roles, where the field device controller implements the master role and the control device controller implements the slave role, the system allows the field device to transmit messages only when resources are sufficient and ensures that only requested messages are transmitted, thereby minimizing security risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the control device controller implements the master role and transmits messages to the field device controller, then the control device can initiate communication, but the field device cannot process all messages within the required time frame due to insufficient resources

Engineering Contradiction:

Improvecontrol device ability to initiate communicationVSAvoidmessage processing throughput

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent inverts the traditional master-slave role assignment by making the field device controller the master and the control device controller the slave. This allows the field device to control message transmission timing, ensuring it can process messages within available resources while maintaining communication functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system dynamically adjusts communication timing based on field device resource availability. The field device master controls when messages are transmitted and processed, adapting to varying resource conditions rather than following fixed timing constraints.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the control device controller transmits unsolicited messages to the field device controller, then communication can be initiated, but security risks increase as other devices could also transmit unsolicited messages

Engineering Contradiction:

Improvecommunication initiation capabilityVSAvoidcommunication security

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

By inverting the master-slave roles, the field device master controls which messages are transmitted and to whom. This prevents unsolicited messages from control devices and other devices, as only the field device master can initiate authenticated communication.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system implements authentication feedback mechanisms where the field device master verifies incoming messages and controls response transmission. This feedback loop ensures only authenticated devices can communicate, blocking unsolicited messages while maintaining legitimate communication flows.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If the field device controller implements the slave role, then the control device can transmit messages, but the field device does not know the transmission time of messages

Engineering Contradiction:

Improvecontrol device message transmissionVSAvoidmessage transmission timing information

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

Inverting the master-slave assignment gives the field device master control over message timing. As master, the field device knows exactly when it transmits and receives messages, preserving timing information that would be lost in traditional slave configurations.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12346077B2System comprising a field device and a control device and method for operating such a system

Publication Date: 2025.07.01 KROHNE S.A.S.

AI summary

A system includes a field device and a control device. The field device includes a field device controller and a field device transmitter. The control device includes a control device controller and a control device transmitter. The field device transmitter and the control device transmitter have a transmission path between them. The field device controller and the control device controller are adapted for bidirectional transmission of messages between one another according to a communication protocol via the field device transmitter, the transmission path, and the control device transmitter. The communication protocol implements the transmission of messages with a master role and a slave role. The field device controller implements the master role and the control device controller implements the slave role. A related method is also disclosed.