CAN Data Frames With Destination Indicators for Mixed-Length Messages
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Solution Overview
Problem
Existing CAN protocols, including CAN FD, are inefficient in transmitting both shorter and longer messages, leading to longer transmission times for messages that are not sufficiently long.
Innovation Solution
A data communication system utilizing a master device and slave devices, where output data frames include a destination indicator and data length indicator, allowing efficient transmission of data to multiple slave devices with varying data lengths, and incorporating a timeout mechanism to handle non-responsive slave devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If CAN FD frame is used to support higher data rates and larger payloads, then data transmission capability is improved, but transmission time increases for shorter messages due to longer control field and CRC field
Solution Approach 1:
The patent segments the data transmission into multiple shorter CAN FD frames, each carrying a portion of the total data payload. By dividing the data into chunks that fit within the optimized frame structure, the system achieves efficient transmission without the overhead penalty of using a single long frame for short messages, thus resolving the contradiction between payload capacity and transmission time.
Solution Approach 2:
The patent dynamically adjusts the data phase bit rate based on the actual data length being transmitted. For shorter messages, it uses a lower bit rate that optimizes the frame transmission time, while for longer messages it switches to higher bit rates. This dynamic adaptation allows the system to maximize efficiency across varying payload sizes, resolving the time-capacity tradeoff.
2Productivity
If a single data frame transmits data to multiple slave devices, then communication efficiency is improved, but data accuracy decreases when data lengths vary among devices
Solution Approach 1:
The patent applies local quality by customizing the data field content for each slave device based on its specific requirements. Each slave device receives data with the appropriate length and format tailored to its needs, while still being transmitted within a single efficient frame structure. This allows the master device to maintain high communication efficiency while ensuring each slave receives accurately formatted data.
Solution Approach 2:
The patent uses preliminary action through the data length indicator field, which is set in advance to specify the exact number of data bytes intended for each slave device. This pre-configured information allows slave devices to correctly interpret and process the incoming data without errors, maintaining data reception accuracy even when transmitting to multiple devices with varying data length requirements.
3Reliability
If timeout mechanism is implemented to handle non-responsive slave devices, then communication reliability is improved, but system complexity increases
Solution Approach 1:
The patent implements a timeout mechanism that uses feedback from slave device responses to trigger appropriate error handling. When a slave device fails to respond within the expected timeout period, the master device detects this through the absence of the expected response signal and initiates error handling procedures. This feedback-based approach improves communication reliability while keeping the control mechanism relatively simple by only activating additional complexity when needed.
Data Source
AI summary
The present disclosure relates to a data communication system and method thereof. According to the present invention, a system for data communication using controller area network (CAN) protocol is provided. The system comprises a master device, and at least one group of slave devices. The at least one group of slave devices comprises multiple slave devices connected to the master device to receive at least one output data frame from the master device. The at least one output data frame includes a destination indicator and a data length indicator. The destination indicator is configurated to indicate multiple slave devices for receiving the at least one output data frame. The data length indicator is configurated to indicate a data length to be received by each slave device in the at least one of slave devices.