Time-Window Scheduling for Time-Critical Industrial Data Streams

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Solution Overview

Problem

Industrial automation systems face issues with communication interruptions and inefficient resource utilization due to time-critical data transmission requirements, leading to potential production downtime and suboptimal use of network resources.

Innovation Solution

A method for operating a communication system that synchronizes periodic time intervals for data transmission, uses quality of service parameters to reserve resources, and allocates individual time windows for control applications, ensuring efficient resource utilization and flexible adaptation to varying requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If credit-based shapers are used to monitor bandwidth and enforce transmission pauses, then bandwidth limitation is achieved, but transmission of control data frames is delayed or interrupted

Engineering Contradiction:
Improvebandwidth limitationVSAvoidtransmission delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the communication network into two distinct types: industrial automation communication devices that handle time-critical control data, and Ethernet communication devices that handle standard data traffic. This segmentation allows each type to operate with its own transmission rules, preventing Ethernet devices from imposing pauses on industrial automation traffic while still enforcing bandwidth limits where applicable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by allowing different transmission characteristics for different device types. Industrial automation communication devices are granted exempt status from credit-based shaper enforcement, enabling them to transmit control data frames without forced pauses. This local differentiation ensures that bandwidth monitoring is applied where appropriate while protecting time-critical communications from degradation.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If Ethernet-based communication networks transmit data frames with large payloads, then network versatility is improved, but resources for real-time data streams are depleted

Engineering Contradiction:
Improvenetwork flexibilityVSAvoidquality of service
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention segments the network into two distinct types: industrial automation communication devices that handle time-critical control data, and Ethernet communication devices that handle standard data traffic. This segmentation allows each type to operate with its own transmission rules, preventing Ethernet devices from depleting resources needed for real-time industrial automation data streams while maintaining network versatility for handling various data types.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If communication interruptions occur in industrial automation systems, then error detection is improved, but production continuity is disrupted

Engineering Contradiction:
Improveerror detectionVSAvoidproduction continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements preliminary action by establishing a protected communication infrastructure for industrial automation devices before problems occur. By pre-defining exempt status for these devices and configuring them to operate independently from credit-based shaper enforcement, the system ensures continuous operation of time-critical control data transmission. This preventive approach maintains production continuity while still allowing error detection mechanisms to function.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3674824B1Method for operating a communication system for transferring time-critical data and communication device
Publication Date: 2023.08.23 SIEMENS AG
  • EP3674824B1 patent drawingFigure 1
  • EP3674824B1 patent drawingFigure 2

AI summary

For data streams running on terminal devices (201, 202) and assigned to selected control applications, an individual time window (411-417) is specified within predefined time intervals. Each time window has an individual cycle duration, which is a multiple of or equal to the general cycle duration. First and second communication devices (101, 102) check for the selected control applications whether a specified time window is available for data transmission. If a time window (411-417) is available, information about the start of the time window within the predefined time intervals is transmitted to the terminal device (201, 202) on which the respective selected control application is running. Data streams assigned to selected control applications are then transmitted according to the information about the start of the individual time window.