Single M-LVDS Ethernet Frame Link for Low-Latency PLC Daisy Chains
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Solution Overview
Problem
Industrial networks using daisy chain topology for PLCs face latency issues and increased complexity, power consumption, and space requirements due to the use of multiple M-LVDS lines for Ethernet MAC frames, which are not compatible with near real-time constraints and hinder easy addition or removal of PLCs.
Innovation Solution
A transmitter module that encodes and serializes Ethernet MAC frames onto a single M-LVDS line using 8b/10b encoding and a serializing unit, and a receiver module that decodes and deserializes frames using a clock data recovery unit, reducing the need for multiple lines and simplifying communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple M-LVDS lines are used to transmit Ethernet MAC frames, then data transmission capability is improved, but power consumption increases
Solution Approach 1:
The patent combines multiple parallel data lines into a single M-LVDS line by implementing 8b/10b encoding and serialization. Multiple data channels are merged into one serialized stream, reducing the number of physical lines from 7 or 11 to just 1, thereby reducing power consumption while maintaining data transmission capability.
Solution Approach 2:
The patent changes the parameter of data representation from parallel bits to serialized 10-bit words. By transforming the data format and using 8b/10b encoding, the system achieves efficient single-line transmission that reduces power consumption compared to multiple parallel lines.
2Productivity
If multiple M-LVDS lines are used to transmit Ethernet MAC frames, then data transmission capability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple data transmission functions into a single M-LVDS line with integrated encoding and serialization logic. This consolidation reduces the complexity of managing multiple separate lines and their associated control circuits.
Solution Approach 2:
The single M-LVDS line is designed to handle multiple functions including data transmission, clock signaling, and frame synchronization through the 8b/10b encoded serialized stream, replacing the need for separate dedicated lines for each function.
3Productivity
If multiple M-LVDS lines are used to transmit Ethernet MAC frames, then data transmission capability is improved, but space requirements increase
Solution Approach 1:
The patent merges multiple physical connection lines into a single M-LVDS line, reducing the board space and routing requirements. The consolidation of 7 or 11 lines into one significantly reduces the physical area needed for connections and associated infrastructure.
4Ease of manufacture
If daisy chain topology is used to connect PLCs, then cost effectiveness is improved, but latency increases
Solution Approach 1:
The 8b/10b encoding and serialization are performed in advance before transmission, allowing efficient packing of data into a single line. This preliminary processing enables faster transmission rates on the single line, reducing latency while maintaining the cost-effective daisy chain topology.
5Ease of manufacture
If daisy chain topology is used to connect PLCs, then cost effectiveness is improved, but adaptability decreases
Solution Approach 1:
The serialized single-line interface provides more flexible data flow control compared to fixed multi-line connections. The system can dynamically adjust transmission rates and handle variable data loads more efficiently, improving adaptability when adding or removing PLCs from the daisy chain.
Data Source
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AI summary
Examples include a transmitter module, a receiver module and a communication system for exchanging Ethernet Medium Access Control frames on a single M-LVDS line.