Master-Slave Bidirectional Data Transmission via Power Line Load Modulation
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Solution Overview
Problem
Existing master-slave systems that transmit data via a power line only allow unidirectional communication, preventing the master device from determining if the slave device has received data and its operational status, leading to potential data loss.
Innovation Solution
Implementing a bidirectional communication method by using voltage level changes on a power line, where the master device outputs a first voltage level change for data transmission and the slave device changes the power line load to produce a second voltage level change for feedback, allowing the master device to receive data on the slave's status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If data is transmitted via only the power line in a master-slave system, then wiring complexity is reduced, but bidirectional communication capability is lost
Solution Approach 1:
The power line is designed to serve multiple functions simultaneously: it provides both power transmission and bidirectional data communication. The master device transmits data to the slave device during a first period, and the slave device transmits feedback data back to the master device during a second period, all through the same power line infrastructure.
Solution Approach 2:
Bidirectional communication is achieved through time-division multiplexing where the power line alternates between different communication directions in different time periods. The master device communicates during a first period, then the slave device communicates during a second period, enabling full-duplex functionality through half-duplex periodic transmission.
2Device complexity
If unidirectional data transmission is implemented from master to slave, then system simplicity is maintained, but data loss occurs due to inability to confirm receipt
Solution Approach 1:
The slave device transmits feedback data back to the master device through the power line during a second period. This feedback indicates whether the slave device has successfully received and processed the data, allowing the master device to confirm data receipt and detect any transmission errors or loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective bidirectional communication through a single power line, ensuring data integrity and simplifying wiring by allowing the master device to confirm data receipt and slave device status, thus preventing data loss.
Implementation Method 1
the master device outputs the voltage signal subject to a first voltage level change to the slave device based on first data via the power line, so that the slave device obtains the first data based on the first voltage level change
Implementation Method 2
the slave device changes load of the power line based on second data, so that the voltage signal on the power line is subject to a second voltage level change, and the master device obtains the second data based on the second voltage level change
Data Source
AI summary
A master-slave system and a data transmission method thereof are provided. The master-slave system includes a slave device and a master device. The master device is coupled to the slave device via a power line. The master device outputs a voltage signal to the slave device via the power line. In a first period, the master device outputs the voltage signal subject to a first voltage level change to the slave device based on first data via the power line, so that the slave device obtains the first data based on the first voltage level change. In a second period, the slave device changes load of the power line based on second data, so that the voltage signal on the power line is subject to a second voltage level change. The master device obtains the second data based on the second voltage level change.