Backplane Time Synchronization Using Passive Unidirectional Links
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing industrial control systems face challenges in efficiently synchronizing I/O modules with cluster managers while maintaining real-time constraints and reliability, especially over half-duplex media.
Innovation Solution
The system employs passive base plates and unidirectional communication lines to synchronize I/O modules with cluster managers without the need for active switches or hubs, allowing for one-way synchronization and eliminating path delay calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If active switches or hubs are used for synchronization, then communication flexibility is improved, but system reliability and cost are worsened due to active components in the backplane
Solution Approach 1:
The patent extracts the active switching function from the backplane and relocates it to external switches connected via fieldbus. The backplane itself becomes passive, containing only unidirectional communication lines and base plates, thereby eliminating the reliability issues associated with active components in the backplane while maintaining communication flexibility through external switching infrastructure.
Solution Approach 2:
The patent introduces external switches as intermediary devices that handle the active switching and synchronization functions. These switches connect to the backplane modules via fieldbus communication, acting as mediators that provide the necessary intelligence without being embedded in the backplane structure, thus separating concerns between the backplane (passive distribution) and the switching logic (active control).
2Reliability
If passive base plates with unidirectional communication lines are used, then system reliability is improved, but communication bidirectionality is worsened
Solution Approach 1:
The patent segments the communication function into separate unidirectional channels: one direction for synchronization signals (from master to slaves) and another direction for data communication (via fieldbus from slaves to master). This segmentation allows each channel to be optimized for its specific purpose while maintaining overall system functionality through the combination of multiple channels.
Solution Approach 2:
The patent adds a temporal dimension to the communication model by implementing time-division multiplexing and synchronized operation cycles. The system alternates between synchronization phases (using unidirectional lines) and data communication phases (using fieldbus), effectively providing bidirectional communication capability through time-separated unidirectional channels.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an industrial system for controlling backplane communication, comprising: a cluster manager (CM) comprising a primary switch (PS) linked to a primary control module (PCM), at least one Input/Output, I/O, module (IOM) comprising a secondary switch (SS) linked to a secondary control module (SCM), a unidirectional communication line (UCL) linking the cluster manager (CM) to the at least one IO module (IOM) through passive base plates (BP), wherein the cluster manager (CM) comprises a transmission port (TPC) and a reception port (RPC) on the unidirectional communication line and the at least one Input/Output module (IOM) comprises a reception port (RPM) on the unidirectional communication line, wherein the primary control module is configured to generate a pulse via the transmission port (TPC) on the unidirectional communication line, wherein, upon reception of the pulse, the primary control module (PCM) is configured to create a primary timestamp from a primary clock of the primary switch and the secondary control module (SCM) is configured to create a secondary timestamp from a secondary clock of the secondary switch, wherein the primary control module (PCM) is configured to send a message via the transmission port on the unidirectional communication line to the secondary control module, the message comprising the primary timestamp, wherein, upon reception of the message, the secondary control module (SCM) is configured to synchronize the secondary clock with the primary clock based on the received primary timestamp and secondary timestamp.