Control Module Data Exchange with Guaranteed Response Intervals

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Solution Overview

Problem

Existing safe control devices in automation technology face challenges in reducing reaction time due to requirements for fail-safe communication, which often result in longer response times and increased costs when implementing specialized communication channels or synchronized clocks.

Innovation Solution

Configuring control modules to ensure specific minimum time intervals between communication events, allowing for improved worst-case analysis without the need for fail-safe communication devices or synchronized clocks, by using redundant data transmission and time monitoring to guarantee defined time characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant data transmission is used for fail-safe communication, then reliability is improved, but response time increases

Engineering Contradiction:

Improvefail-safe communication reliabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by sending process data before the minimum duration expires, and prepares to send again if acknowledgment is not received. This allows the system to have already initiated transmission actions that can be quickly completed or abandoned, rather than waiting passively for response time to elapse.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses periodic transmission attempts with a defined minimum duration between them. By structuring redundant transmissions as periodic events with guaranteed minimum intervals, the system can predict response times more accurately while still achieving fail-safe communication through multiple transmission opportunities.

Inventive Principle:

Principle #19Periodic action

2Loss of time

If fail-safe communication channels or synchronized clocks are implemented, then response time characteristics are improved, but device complexity increases

Engineering Contradiction:

Improveresponse time characteristicsVSAvoidcommunication channel complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The system uses the existing communication infrastructure to serve dual purposes: normal process data transmission and fail-safe acknowledgment. The same communication channel that carries process data also carries acknowledgments, eliminating the need for separate fail-safe communication channels while maintaining response time guarantees.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The communication channel is designed to perform multiple functions: transmitting process data from first to second control module, transmitting acknowledgments from second to first control module, and providing timing references for worst-case analysis. This multi-functionality eliminates the need for specialized fail-safe communication hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of time

If fail-safe communication devices or synchronized clocks are used, then response time is improved, but manufacturing cost increases

Engineering Contradiction:

Improveresponse timeVSAvoidimplementation cost

Core Design Contradiction:

Loss of timeVSEase of manufacture

Solution Approach 1:

The system uses standard, inexpensive communication channels and modules rather than costly fail-safe specialized equipment. By relying on software-based timing mechanisms and redundant transmission logic rather than hardware synchronization, the system achieves fail-safe communication at lower manufacturing cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system replaces mechanical/hardware solutions (synchronized clocks, dedicated fail-safe communication channels) with software-based solutions (timing measurements, acknowledgment protocols, worst-case analysis algorithms). This substitution maintains functional safety while reducing hardware complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20230236558A1Process Data Exchange with Guaranteed Minimum Transmission Intervals

Publication Date: 2023.07.27 PILZ GMBH & CO KG

AI summary

A control device includes first and second control modules. The first control module is configured to generate process data at t1, send the process data to the second control module via a communication channel, receive a response to the process data, and process the process data at t4. The second control module is configured to receive the process data from the first control module, process the process data at t2, generate the response at t3, and send the response to the first control module. The times t1, t2, t3, and t4 are in chronological order. In various implementations, the first and second control modules jointly guarantee a minimum duration Δ1 between t1 and t2. In various implementations, the second control module guarantees a minimum duration Δ2 between t2 and t3. In various implementations, the first and second control modules jointly guarantee a minimum duration Δ3 between t3 and t4.