Master Device Ring Path Switching to Prevent Reverse Cyclic Data
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Solution Overview
Problem
In junction redundancy ring wiring, cyclic data can be erroneously input into the master when a disconnected portion is reconnected, leading to reverse cyclic data circulation.
Innovation Solution
A master device that manages slave devices connected to a ring wiring, capable of configuring a first path for data transfer and a second path for loopback. The master device transmits an instruction to switch the second path to the first path when the path is recovered from disconnection, and sends new data after a propagation delay time based on the ring wiring's delay time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loopback function is enabled in slave devices for redundancy, then reliability of data transmission is improved, but cyclic data may circulate in the ring wiring when disconnection is recovered, causing erroneous input in the master
Solution Approach 1:
The master device transmits an instruction to switch from the second path (loopback) to the first path (normal transmission) before new data is sent out. This preliminary action ensures that the path switching is completed in advance, preventing cyclic data from circulating when the disconnection is recovered. The instruction includes opening instructions for both the first port and second port, with the second port opened first to ensure proper path transition.
Solution Approach 2:
The patent introduces a path switching mechanism as an intermediary between the loopback function and data transmission. The master device controls the slave devices to switch paths by transmitting specific instructions that manipulate the opening/closing of ports. This intermediary control mechanism ensures that the loopback function is deactivated at the appropriate time, preventing cyclic data circulation while maintaining transmission reliability.
2Productivity
If new data is sent out immediately after path recovery, then productivity is improved, but cyclic data may still circulate causing errors
Solution Approach 1:
The master device transmits the path switching instruction before sending out new data, ensuring that the path transition is completed in advance. This preliminary action maintains productivity by minimizing the waiting time while ensuring reliability by preventing cyclic data circulation. The system waits only for the instruction transmission and processing time, not for an extended period.
Solution Approach 2:
The slave devices provide feedback to the master device regarding their path status. When the master device transmits the opening instruction for the second port, the slave device processes this instruction and switches its internal path configuration. This feedback mechanism ensures that the path switching is properly executed before new data is sent, maintaining both productivity and reliability.
Data Source
AI summary
A plurality of slaves include a first slave constituting the start and end points of a ring wiring and a plurality of second slaves connected between the start and end points, the ring wiring being capable of configuring a first path via which the second slaves cause data accepted from the start point side to be cyclically transferred to the end point side, and a second path for each slave to loop back the data from the device itself when the path between the slave and an adjacent slave is disconnected. When the path is recovered from the disconnection, a master transmits a command for switching the second path to the first path to the slave that carries out the loopback, and sends out data after the elapse of a time based on a propagation delay time from the time of this transmission.