Industrial Network Nodes Switching Between Serial Shift and Switch Modes
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Solution Overview
Problem
Industrial control networks face challenges in increasing transmission rates and enabling bidirectional communication between nodes without relying on a single master device, particularly in complex systems where multiple slave devices need to communicate directly.
Innovation Solution
An industrial network architecture with at least two end nodes operating in switch mode and intermediate nodes capable of toggling between switch and serial shifting modes, allowing for bidirectional communication and data insertion/extraction within a single I/O scan cycle, using a network medium and synchronized protocol like IEEE 1588 for time coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single master device generates and circulates data frames through slave devices in a ring topology, then data transmission can be achieved, but communication efficiency deteriorates because slave devices cannot communicate directly and must wait for master device cycles
Solution Approach 1:
The network is segmented into end nodes and intermediate nodes. End nodes operate in switch mode to initiate frames, while intermediate nodes operate in serial shift mode to pass frames efficiently. This segmentation allows direct communication between slave devices without requiring a single master device to mediate all communications, thereby improving communication efficiency and reducing delays.
Solution Approach 2:
Intermediate nodes can dynamically toggle between serial shift mode and switch mode. In serial shift mode, they efficiently pass frames; when direct communication is needed, they switch to switch mode to initiate or receive frames. This dynamic mode switching enables flexible communication patterns that improve overall network productivity while minimizing communication delays.
2Productivity
If the transmission rate is increased to handle more devices within a fixed control cycle, then device connectivity improves, but system reliability may deteriorate due to higher transmission errors and interference
Solution Approach 1:
The network uses periodic I/O scan cycles with defined phases. During the first phase, intermediate nodes operate in serial shift mode for efficient data passing. During the second phase, they switch to switch mode for direct communications. This periodic switching allows the system to achieve high transmission rates while maintaining reliability through structured, predictable communication patterns that minimize interference.
Solution Approach 2:
The serial shift mode enables continuous frame passing without the stop-start nature of traditional master-slave cycles. Frames can be efficiently transmitted through intermediate nodes in serial shift mode, maintaining continuous useful action. When direct communication is needed, the transition to switch mode ensures no loss of reliability, as the system maintains controlled communication phases throughout.
3Adaptability or versatility
If multiple master devices are allowed to communicate with different slave devices, then network versatility improves, but device complexity increases due to coordination requirements
Solution Approach 1:
Intermediate nodes are designed with multi-functionality, capable of operating in both serial shift mode and switch mode. This universality allows any intermediate node to function as a master device when needed, enabling multiple master-s slave device communications without requiring dedicated master devices. The standardized mode switching mechanism keeps complexity manageable while achieving high network versatility.
Solution Approach 2:
The dynamic mode toggling capability allows intermediate nodes to adapt their function based on communication needs. A node can switch from serial shift mode to switch mode to become a temporary master device, then return to serial shift mode. This dynamic behavior provides network versatility without permanent configuration complexity, as nodes can assume different roles as needed.
4Adaptability or versatility
If slave devices insert data into data frames for upstream communication, then bidirectional communication is enabled, but transmission time increases due to multiple communication cycles required
Solution Approach 1:
The network communication is segmented into two distinct phases within each I/O scan cycle. The first phase handles upstream communications where slave devices insert data into frames. The second phase handles downstream communications where master devices receive data. This segmentation allows bidirectional communication to occur within a single coordinated cycle rather than requiring multiple separate cycles, reducing overall communication time while maintaining full bidirectional capability.
Solution Approach 2:
The periodic switching between serial shift mode and switch mode creates structured communication phases. During serial shift mode, frames are passed efficiently with data insertion. During switch mode, direct bidirectional communications occur. This periodic structure enables comprehensive bidirectional communication within a single I/O scan cycle, eliminating the need for multiple cycles and reducing communication time.
Data Source
AI summary
An industrial network with bidirectional communication for real time control includes nodes selectively operable in either a switch mode or a serial shifting mode. Nodes operating in the switch mode are capable of initiating data frames for transmission on the network and receiving data frames from the network. Nodes operating in either the switch mode or the serial shifting mode are capable of extracting and/or inserting data into a data frame as it is transmitted through that node. An initialization procedure determines end nodes and intermediate nodes within the network. The end nodes are configured to initially operate in the switch mode and the intermediate nodes are configured to initially operate in the serial shifting mode. The intermediate nodes are additionally operable to selectively toggle between operation in switch mode and serial shift mode and may operate in both modes during a single scan cycle.