Secondary Controller Database Sync for Redundant Path Diagnostics
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Solution Overview
Problem
In industrial process control and automation systems, secondary devices in redundant controller pairs lack comprehensive diagnostic capabilities, relying on primary device database knowledge for full operational assessment, which limits their ability to seamlessly take over primary functions during failures.
Innovation Solution
The method involves synchronizing the primary device's control database with the secondary device, using a tracking device driver to update the secondary device's database with changes, and performing diagnostic testing on communication connections and paths to ensure the secondary device can independently assess its operational functionality and report faults before assuming primary roles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary device performs full operational diagnostic assessment independently, then diagnostic coverage and reliability are improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent applies the copying principle by having the secondary device create and maintain a copy of the primary device's control database. This copy contains all necessary system knowledge, I/O module information, and diagnostic data structures. By copying the database rather than requiring independent assessment capabilities, the secondary device achieves full diagnostic coverage while avoiding the complexity of independent hardware assessment functionality.
Solution Approach 2:
The patent implements preliminary action by continuously synchronizing the secondary device's control database with the primary device's database before any failover event occurs. This ensures that the secondary device already possesses all current system knowledge, I/O module configurations, and diagnostic information in advance, enabling immediate full operational assessment upon becoming primary without requiring complex real-time independent assessment capabilities.
2Reliability
If the secondary device synchronizes with the primary device's control database continuously, then operational functionality assessment is improved, but communication network bandwidth and processing overhead increase
Solution Approach 1:
The patent applies periodic action by implementing continuous synchronization of the control database between primary and secondary devices. Rather than syncing only on demand or at fixed intervals, the synchronization occurs continuously in the background, ensuring the secondary device always has current system knowledge while allowing the primary device to focus on control operations. This periodic/continuous approach balances up-to-date information availability with manageable communication overhead.
3Measurement precision
If the secondary device tests all communication connections and paths to I/O modules, then fault detection capability is improved, but diagnostic testing time and system disruption increase
Solution Approach 1:
The patent implements preliminary action by having the secondary device perform comprehensive diagnostic testing of all communication connections and paths to I/O modules in advance, while still operating as secondary. This includes testing peer-to-peer communication paths and I/O module accessibility. By completing these time-consuming diagnostic tests beforehand, the system ensures rapid fault detection capability when the secondary device becomes primary, without causing disruption to ongoing control operations.
Data Source
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AI summary
A method for use by a primary device associated with a secondary device of a redundant pair, the primary device issuing a synchronization request to its control database causing the primary device to send a tracked memory file storage of the primary device to the secondary device to update the secondary device control database and to periodically send on request of the primary device the cached changes made in the primary device to the secondary device to update the secondary device control database. The secondary device using the updated control database to identify communications connections and paths to I/O modules and peer devices assigned to the secondary device and to perform diagnostic testing of the communications connections and paths identified by the interrogation and send diagnostic messages upon detection of faults in the communication connections and paths identified.