I/O Bus Topology Discovery for Accurate Module Self-Addressing

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Solution Overview

Problem

Current methods for addressing I/O-Modules in Building Automation Systems are costly and require additional hardware or complex procedures, leading to inefficiencies and waste, while existing bus communication technologies struggle with accurate distance measurement for closely spaced modules.

Innovation Solution

An automatic method that measures the distance of each I/O-Module from a controller via a serial bus, assigning addresses based on these distances, using a conductor length within the module that is intentionally longer than necessary to enhance measurement accuracy, allowing for unambiguous addressing and simplified customization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the conductor length within each I/O-Module is made as short as possible (direct connection), then the total bus cable length is reduced and robustness is increased, but the distance measurement accuracy deteriorates because the measurement resolution cannot distinguish between closely spaced modules

Engineering Contradiction:
Improverobustness of physical layerVSAvoiddistance measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the conductor length parameter from minimal (direct connection) to intentionally extended length. This parameter modification enables the distance measurement to achieve sufficient resolution for unambiguous module addressing while maintaining the multi-drop bus topology benefits

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an additional dimensional aspect to the conductor routing within the I/O-Module housing. Instead of a straight line connection, the conductor follows an extended path (e.g., meandering route) that increases the effective length without changing the physical module position, thereby enabling measurement discrimination

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If electromechanical address keys are used for addressing, then each I/O-Module can be uniquely addressed, but the system complexity and cost increase due to requiring address decoders and multiple key sets

Engineering Contradiction:
Improveaddressing capabilityVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The I/O-Module automatically determines its own address by measuring the distance from the controller based on the conductor length. This self-addressing capability eliminates the need for manual configuration using electromechanical keys and decoders, reducing system complexity while maintaining unique addressing

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical addressing system (electromechanical keys and decoders) with an electrical measurement system. The address is determined through electrical distance measurement via the conductor length rather than mechanical key configuration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If commissioning tools with Bluetooth, NFC, or USB connections are used for addressing, then I/O-Module addresses can be configured, but additional hardware requirements and cost increase

Engineering Contradiction:
Improveaddress configurationVSAvoidhardware requirements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The I/O-Module performs self-addressing through automatic distance measurement via the serial bus and conductor length. This eliminates the need for external commissioning tools with Bluetooth, NFC, or USB connections, reducing hardware requirements while maintaining addressing capability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The serial bus serves multiple functions: it provides both the communication pathway for data transmission and the measurement pathway for distance measurement. This multi-functionality eliminates the need for separate commissioning tools and their associated hardware interfaces

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

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables convenient and cost-effective addressing of I/O-Modules, simplifying the customization process by ensuring accurate distance measurement and reducing the need for manual intervention or additional hardware.

Implementation Method 1

an electrical conductor within the housing between the two ports, wherein a conductor length of the electrical conductor between the two ports of the serial bus is longer than the shortest distance between the two ports

Methodology Applied
Scientific EffectElectrical signal transmission: Conduction (electrical)

Data Source

PatentEP4704406A1Enhanced accuracy of io-bus topology discovery
Publication Date: 2026.03.04 SIEMENS SCHWEIZ AG
  • EP4704406A1 patent drawingFigure 1~2
  • EP4704406A1 patent drawingFigure 3
  • EP4704406A1 patent drawing

AI summary

Customization of Building Automation Systems shall be made more comfortable. Thus, there is provided a method of automatically addressing a plurality of I/O-Modules (1) being connected to a controller (3) serially by a serial bus (2), the method includes the steps of: - automatically measuring (S2) a respective distance from the controller (3) to each of the I/O-Modules (1) via the serial bus (2), - wherein the automatically measuring (S2) is performed with a pregiven distance resolution (dm), - wherein a conductor length within each I/O-Module (1) between respective two external ports of the serial bus (2) is longer than the shortest distance between the two external ports and longer than the pregiven distance resolution (dm), and - automatically addressing (S3) all I/O-Modules (1) in dependence of the respective measured distance from the controller (3).