MCC Multidrop Make-and-Break Network for Hot-Swappable Units

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Solution Overview

Problem

Existing multidrop systems in motor control centers (MCCs) face challenges in maintaining network and subnet integrity when units are inserted or removed, leading to disturbances.

Innovation Solution

A multidrop make and break system with trunk and branch network components that allow MCC withdrawable units to be coupled and decoupled without disrupting the trunk network, using a multidrop cable with SPE, SP, and NP pairs, and a select line for communication and power management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a unit of the MCC is inserted or removed, then the flexibility and maintainability of the MCC system is improved, but the network and subnet are disturbed

Engineering Contradiction:

Improveflexibility of MCC unit installationVSAvoidnetwork integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system divides the network into a trunk network and a sub-network. The trunk network maintains continuity while the sub-network is selectively connected or disconnected based on unit insertion/removal. This segmentation allows individual units to be added or removed without affecting the overall network integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A multidrop make and break device acts as an intermediary between the trunk network and the sub-network. This device controls the connection state, allowing the sub-network to be isolated when units are removed and connected when units are installed, thereby preventing network disturbance during unit changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If units are quickly inserted or removed, then the productivity of MCC maintenance is improved, but the network disturbance occurs

Engineering Contradiction:

Improvespeed of unit installationVSAvoidnetwork disturbance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The multidrop make and break device is pre-configured to control the connection timing. Before a unit is removed, the device预先 disconnects the sub-network from the trunk network. This preliminary action ensures that network disturbance is avoided even when units are quickly installed or removed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The trunk network maintains continuous operation throughout the unit installation/removal process. By keeping the trunk network connected and operational while selectively isolating the sub-network, the system ensures uninterrupted communication and power distribution for remaining units.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentEP4161000B1Multidrop make and break system

Publication Date: 2025.12.03 ROCKWELL AUTOMATION TECH INC

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AI summary

A multidrop system configured to be installed within a motor control center (MCC) of an industrial automation system includes a trunkline. The trunkline includes multiple multidrop make and break devices connected through a trunkline cable. Each of the multidrop make and break device includes a first network component, and a second network component. The first network component is configured to form a first subnet over the trunkline. The second network component is configured to couple a MCC withdrawable unit and form a second subnet over a branchline that connects one or more nodes within the MCC withdrawable unit. The multidrop make and break device is configured to couple the MCC withdrawable unit to, and decouple the MCC withdrawable unit from, the second network component without disrupting the first subnet.