Relay PLC Network Segmentation for Communication Fault Isolation
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Solution Overview
Problem
In existing PLC systems, monitoring and troubleshooting of multiple PLCs connected via a network is inconvenient, especially when communication abnormalities occur, as it is difficult to identify the source of the issue due to complex network paths and various potential causes, leading to lengthy problem-solving times.
Innovation Solution
A PLC system where one PLC is designated as a relay, allowing the development support device to connect online and switch between PLCs, dividing the communication path into sections between the device and the relay PLC and between the relay and target PLC, enabling quick identification of abnormal communication sources through periodic testing and routing table analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PLCs are connected via a network for monitoring and control, then ease of operation is improved, but difficulty of detecting and measuring communication abnormalities increases
Solution Approach 1:
The communication path is segmented into multiple sections by introducing a relay PLC. The system divides the network into sections: from the personal computer to the relay PLC, and from the relay PLC to the target PLC. This segmentation allows isolation and individual testing of each section to identify where communication abnormalities occur, transforming a difficult single-path diagnosis into manageable sectional diagnostics.
2Ease of operation
If a relay PLC is introduced to monitor target PLCs via network, then ease of operation is improved, but device complexity increases
Solution Approach 1:
A relay PLC is introduced as an intermediary device between the personal computer and the target PLCs on the network. This intermediary PLC handles communication routing and can be switched between different target PLCs, allowing the personal computer to monitor multiple PLCs without direct physical reconnection. The relay PLC acts as a mediator that simplifies the overall system operation despite adding one more device to the network.
3Ease of operation
If physical cable switching is avoided by using network connection, then ease of operation is improved, but time required for troubleshooting increases
Solution Approach 1:
The system performs preliminary actions by establishing a relay PLC connection structure before troubleshooting is needed. The relay PLC is pre-configured with routing tables and communication paths are pre-established. When communication abnormalities occur, the system can quickly test each section by switching the relay PLC's connection destination, rather than having to physically trace through complex network paths. This preliminary setup enables rapid sectional diagnosis and reduces troubleshooting time.
Data Source
AI summary
A programmable controller system comprises networks including a plurality of programmable controllers and a development support device. One of the programmable controllers is set as a relay programmable controller. The development support device is used by online-connecting to the relay programmable controller via a communication line and by switching connecting destination to a target programmable controller on the networks during a state of online-connecting to the relay programmable controller.