Redundant Controller Mode Management via Readiness Signals
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Solution Overview
Problem
Current industrial process control systems face challenges in reliably managing redundant controller modules, particularly in ensuring seamless switchover and efficient operation of master/slave modes in remote terminal units (RTUs) across complex network topologies and diverse industrial settings.
Innovation Solution
The implementation of mode management circuitry in redundant controller modules that can identify and assign master or slave modes based on readiness and takeover signals, allowing for automatic switchover and hot-swap capabilities without requiring clock signals, ensuring continuous operation and rapid role switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware-based state machine control is used for redundant controllers, then switching between controllers can be implemented, but the system complexity increases and switchover speed is limited
Solution Approach 1:
The patent replaces hardware-based state machine control with a software-based master/slave management approach. The mode management circuitry uses firmware or software logic to determine master/slave states and handle failover, eliminating the need for complex hardware state machines while achieving the same redundancy and switching functionality.
Solution Approach 2:
The patent changes the control parameter from hardware state machine outputs to software-managed mode indicators. The mode management circuitry dynamically determines controller states through software logic that evaluates readiness signals and takeover requests, allowing faster and more flexible switching compared to fixed hardware state machines.
2Ease of operation
If traditional master/slave assignment is used without readiness checking, then simple control is achieved, but system reliability decreases during failover
Solution Approach 1:
The patent implements readiness checking before master/slave assignment by having the mode management circuitry evaluate whether a controller is ready to assume the master role before actually assigning the mode. This preliminary assessment ensures that failover only occurs to a fully prepared controller, enhancing system reliability while maintaining operational simplicity.
Solution Approach 2:
The patent incorporates feedback mechanisms where controllers exchange readiness signals and takeover requests with each other. The mode management circuitry continuously monitors these feedback signals to determine appropriate master/slave assignments, ensuring that failover decisions are based on real-time system state information.
3Measurement precision
If clock signals are required for controller synchronization, then precise timing is achieved, but hot-swap capability is limited
Solution Approach 1:
The patent extracts the clock signal requirement from the controller synchronization mechanism. The mode management circuitry handles master/slave assignment and timing independently of external clock signals, allowing controllers to be hot-swapped without requiring precise clock synchronization during the transition process.
Solution Approach 2:
The patent implements dynamic master/slave assignment that can occur at any time without being constrained by clock cycle boundaries. The mode management circuitry can transition controllers between modes immediately when readiness conditions are met, providing both precise timing control and flexible hot-swap capability.
Data Source
Figure 1~3A
Figure 2~3B
Figure 4
AI summary
A system comprising first and second redundant controller modules (202a-202b), each controller module comprising mode management circuitry (400a-400b) configured to identify whether the corresponding controller module operates in a master mode or a slave mode. The mode management circuitry in each controller module is configured to couple to the mode management circuitry in the other controller module. The mode management circuitries in the controller modules are configured to collectively operate so that one of the controller modules is assigned the master mode and the other of the controller modules is assigned the slave mode. At least one of the mode management circuitries in the controller modules is configured to assign the master mode to the corresponding controller module based on a takeover signal (510a) when the mode management circuitry in the corresponding controller module is ready for use.