Slave Device Cut-Through Switching for Network Traffic Reduction
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Solution Overview
Problem
In networks with a large number of slave devices, the increase in data traffic and transmission time due to the need for multiple control messages from a master device leads to difficulties in real-time control, and existing solutions like EtherCAT communications face limitations in data size and transmission delay.
Innovation Solution
Grouping slave devices allows a master device to transmit control messages containing group data items, enabling cut-through switching and varying data sizes, which reduces data traffic and transmission time by allowing simultaneous transmission and processing of messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a master device transmits separate control messages to each slave device, then each slave device can be controlled individually, but data traffic increases and transmission time increases as the number of slave devices increases
Solution Approach 1:
The patent combines multiple control messages for different slave devices into a single control message that contains control data for multiple slave devices. This control message is transmitted once from the master device to the first slave device, then sequentially forwarded through the slave device chain. This merging approach reduces the number of transmissions from N separate messages to 1 message, directly addressing the time loss issue while preserving individual control capability through the inclusion of device-specific control data for each slave device in the consolidated message
2Loss of time
If a master device transmits a single control message to all slave devices using cut-through switching, then data transmission time is reduced, but the data size is limited by fixed field sizes
Solution Approach 1:
The patent introduces dynamic data field structures that can be adjusted based on the specific requirements of each slave device. Instead of fixed field sizes, the control message includes data fields with variable lengths that can be extended or contracted. The system dynamically allocates data field sizes according to the actual data transmission needs of each slave device, allowing the control message to adapt to different data size requirements while maintaining the efficient single-message transmission approach
Solution Approach 2:
The patent changes the parameter of data field size from a fixed value to a variable parameter. The control message structure includes data fields whose sizes can be modified based on the communication requirements between the master device and slave devices. This parameter change enables the system to handle both small and large data transmissions within a single control message framework, resolving the contradiction between transmission speed and data size flexibility
3Reliability
If slave devices process control messages sequentially, then data collision is avoided, but transmission delay increases linearly with the number of slave devices
Solution Approach 1:
The patent implements a preliminary action mechanism where the control message is transmitted to the first slave device in the chain before any processing occurs. The control message contains pre-configured control data for all slave devices in the chain. Each slave device performs cut-through switching, forwarding the message to the next device without waiting for processing completion, while simultaneously extracting and applying its own control data. This preliminary transmission approach allows all slave devices to receive their control data in parallel, reducing transmission delay while maintaining data collision avoidance through the predetermined message structure
4Device complexity
If the control message contains fixed-size data fields for each slave device, then message structure is simple, but the size of data to be transmitted is limited
Solution Approach 1:
The patent segments the control message into a header portion and multiple data fields, where each data field corresponds to a specific slave device. The header contains routing information and the number of data fields. Each data field can be independently configured with appropriate size based on the requirements of the corresponding slave device. This segmentation allows the system to maintain a simple overall message structure while providing flexible data field sizes within the message, resolving the contradiction between structural simplicity and transmission capacity
Data Source
AI summary
Disclosed herein are embodiments of a method for controlling a slave device in a system including a master device and a plurality of groups of slave devices. In one embodiment, the method includes generating, by the master device, a control message containing group data items each corresponding to the respective groups to transmit the control message to a particular group; transmitting, by a slave device included in the particular group, the control message to a next group; extracting, by the slave device, a group data item from the control message after the transmitting the control message; extracting/writing, by the slave device, data from/onto the group data; and transmitting, by the slave device, the group data to the master device after completing the extracting/writing.