Ring Bus Automation System Dual Master Redundancy
Solution Overview
Problem
Existing master-slave automation systems face challenges in achieving high fault tolerance and efficient reconfiguration of telegram transmission paths, especially in manufacturing and process automation, due to issues like route errors and master unit failures.
Innovation Solution
The automation system incorporates a ring-shaped data bus with multiple subscribers, including two master units and two distributors, which allow for automatic reconfiguration of the telegram transmission path in real time by switching between different operating modes and using pre-stored switching control sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single master unit is used in the automation system, then the device complexity is reduced, but the fault tolerance deteriorates when the master unit fails
Solution Approach 1:
The system changes the operational state of the second master unit between standby mode and active control mode. When the first master unit fails, the second master unit transitions from standby to active, taking over control functions. This parameter change (operational state) enables fault tolerance without permanently duplicating active control components.
Solution Approach 2:
The second master unit is pre-configured with switching control sets and maintains a connection to the data bus in standby mode before failure occurs. This preliminary preparation allows immediate takeover of control functions when the first master unit fails, ensuring continuous operation without interruption.
2Reliability
If additional hardware is added for substitute master unit, then the fault tolerance is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The second master unit is designed with multi-functionality, serving both as a standby unit and as an active control unit when needed. It contains switching control sets that enable it to perform control functions for both itself and the first master unit, eliminating the need for dedicated backup hardware and reducing overall system complexity.
Solution Approach 2:
The functionality of the substitute master unit is merged with the second master unit. The second master unit combines standby capabilities with active control capabilities, consolidating multiple functions into a single unit rather than requiring separate dedicated backup hardware.
3Reliability
If telegram transmission path is not reconfigured after failure, then the system operation continues, but the reliability deteriorates due to route errors
Solution Approach 1:
The system implements feedback through the ring-shaped data bus structure, where telegrams circulate and return to the master unit. This circular feedback path enables automatic detection of transmission issues and provides the mechanism for reconfiguration by allowing telegrams to traverse alternative paths around the ring when failures occur.
Solution Approach 2:
The telegram transmission path is made dynamic through the switching control sets that can redirect telegram flow between different paths in the ring structure. This dynamic reconfiguration capability allows the system to adapt to failures by changing the active transmission path without requiring permanent structural changes.
Data Source
AI summary
An automation system has a plurality of subscribers including a first primary unit, first distributor, second primary unit, second distributor, and at least another subscriber unit. First and second transmitting/receiving devices of the first and second distributor are connected via a ring-shaped data bus. In a first mode, the first distributor forwards telegrams received from the first primary unit to the first transmitting/receiving device, and forwards telegrams received by the second transmitting/receiving device to the first primary unit. The second distributor also forwards first telegrams received by the first transmitting/receiving device to the second transmitting/receiving device. In a second mode, the second distributor forwards telegrams received by the second primary unit to the second transmitting/receiving device, and the second distributor forwards telegrams received by the first transmitting/receiving device to the second primary unit. The first distributor also forwards telegrams received by the second transmitting/receiving device to the first transmitting/receiving device.