Point-to-Point Backplane Bypass for Bumpless RIUP Modules
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Solution Overview
Problem
Conventional point-to-point backplane arrangements in industrial control devices disrupt data communications when a module is removed or inserted, lacking Removable and Insertion Under Power (RIUP) functionality.
Innovation Solution
A passive bypass data switch arrangement with a make-before-break mechanism and varying PCB edge pad lengths ensures continuous data communication during module insertion and removal, using a normally closed switch and loopback connections to maintain connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional point-to-point backplane arrangement is used, then high data communication rates (100 Mbps - 1 Gbps) are achieved, but data communications are interrupted when a module is removed or inserted
Solution Approach 1:
The bypass switch is pre-configured in a closed position during normal operation, ready to activate immediately when a module is removed. The make-before-break mechanism preliminarily establishes the bypass connection before breaking the original data path, ensuring no interruption in communication.
Solution Approach 2:
The bypass switch acts as an intermediary element that provides an alternative data path when the primary module connection is broken. It mediates between the upstream and downstream modules, allowing data to flow through the bypass path when the module is removed or inserted.
2Reliability
If an active mounting base with powered bypass switch is used to enable RIUP, then data communication continuity is maintained during module insertion and removal, but device complexity and cost increase
Solution Approach 1:
The passive bypass switch automatically changes state based on module presence without requiring external control signals or powered components. The mechanical insertion or removal of the module directly opens or closes the bypass switch through contact-making and contact-breaking, eliminating the need for active control circuitry.
Solution Approach 2:
The passive bypass switch uses simple mechanical contacts instead of complex active components. This simpler, less expensive approach achieves the same RIUP functionality without requiring powered mounting bases, reducing overall system complexity and cost.
3Reliability
If PCB edge pads of varying lengths are used, then the insertion timing sequence is controlled to enable bumpless RIUP, but manufacturing precision requirements increase
Solution Approach 1:
The PCB edge pads are deliberately designed with asymmetric lengths, where the first edge pad extends further than the second edge pad. This asymmetric geometry creates the required timing sequence during insertion, ensuring that the bypass switch closes before the data connection is made, without requiring complex positioning tolerances.
Data Source
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AI summary
Disclosed is an industrial control device including a point-to-point backplane/point module architecture providing RIUP (Removal and Insertion Under Power) functionality where data communications between modules is maintained after the removal of a point module from the backplane According to an exemplary embodiment, a backplane includes a plurality of passive mechanical bypass switches controlled by the insertion and removal of respective point modules, whereby data communicated bypass a removed point module interface and point-to-point data communications are provided to an inserted point module after an initial routine is executed by a microcontroller associated with the inserted point module.