Automatic CAN Bus Termination via Modular Jack Detection

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Solution Overview

Problem

CAN bus networks often experience noise distortions and data corruption due to improper termination, which can lead to communication failures and require manual adjustment of termination plugs when devices are added or removed, posing challenges for end-users.

Innovation Solution

An automatic termination mechanism for CAN bus networks using modular jacks that detect the presence or absence of a plug to enable or disable termination, incorporating a resistive element and switch to automatically manage the termination of the bus, ensuring proper termination when no plug is inserted and disabling it when a plug is present.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual termination plugs are used at each end of the CAN bus, then proper signal termination is achieved, but device complexity and ease of operation deteriorate due to required manual installation and reconfiguration

Engineering Contradiction:
Improvesignal termination reliabilityVSAvoidtermination configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The modular jack assembly automatically detects whether a plug is inserted and self-configures the termination resistors accordingly. When no plug is inserted, the jack enables termination resistors to terminate the CAN bus. When a plug is inserted, the jack automatically disables the termination resistors. This self-service mechanism eliminates manual configuration while maintaining proper signal termination.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention merges the termination function with the modular jack assembly itself, combining the plug receptacle and termination resistor control into a single integrated component. This eliminates the need for separate termination plugs and simplifies the overall system by integrating multiple functions into one device.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If separate termination plugs are used for each CAN bus end, then proper termination is achieved, but ease of operation worsens due to manual installation and reconfiguration requirements

Engineering Contradiction:
Improvebus termination reliabilityVSAvoidtermination setup ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The modular jack assembly performs automatic detection and self-configuration of termination resistors based on plug presence. The system monitors whether a plug is inserted into the jack and automatically enables or disables the termination resistors accordingly, eliminating manual intervention and simplifying operation for end users.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The modular jack assembly serves multiple functions: it acts as both a plug receptacle for device connections and an automatic termination controller. This multi-functionality eliminates the need for separate termination plugs and simplifies the system by combining connection and termination management into a single universal component.

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

3Reliability

If termination plugs are manually reconfigured when devices are added or removed, then proper termination is maintained, but loss of time increases due to manual adjustment requirements

Engineering Contradiction:
Improvetermination accuracyVSAvoidreconfiguration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The modular jack assembly continuously monitors plug presence and automatically adjusts termination resistor states in real-time. When devices are added or removed from the CAN bus, the affected jack assemblies automatically detect the change and reconfigure their termination settings without requiring manual intervention, eliminating reconfiguration time while maintaining termination accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements feedback through automatic detection of plug presence or absence in the modular jack. This feedback mechanism triggers automatic reconfiguration of the termination resistors, ensuring proper termination is maintained dynamically as the network topology changes, without requiring manual time-consuming adjustments.

Inventive Principle:
Principle #23Feedback

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

This solution reduces human error, eliminates the need for separate termination plugs, and provides an out-of-the-box solution by automating the termination process, ensuring reliable communication and simplifying the installation of CAN bus networks.

Implementation Method 1

incorporating a resistive element and switch to automatically manage the termination of the bus

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP2684139B1Can bus automatic line termination
Publication Date: 2018.04.11 SCHNEIDER ELECTRIC IT CORP
  • EP2684139B1 patent drawingFigure 1
  • EP2684139B1 patent drawingFigure 2
  • EP2684139B1 patent drawingFigure 3A

AI summary

A network interface includes a receptacle configured to receive a plug, a first contact and a second contact each disposed in the receptacle, and a combination of a resistive element and a normally closed switch arranged in series with each other. The combination is coupled between the first contact and the second contact, and has a first configuration in which the switch is opened responsive to a presence of the plug within the receptacle, and a second configuration in which the switch is closed responsive to an absence of the plug from the receptacle.