Redundant Output Assembly Wire Break Diagnosis
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Solution Overview
Problem
Conventional redundant output assemblies in automation technology require additional wiring for communication, leading to potential premature diagnosis of wire breaks due to voltage fluctuations, which can result in false alarms and unnecessary process interruptions.
Innovation Solution
A method where the first output assembly evaluates a current and applies a test criterion, and if satisfied, the second output assembly switches off its voltage for a predetermined time, allowing the first assembly to verify if a current still flows, thus distinguishing between actual and false wire break diagnoses, eliminating the need for additional communication wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If additional communication wiring is provided between redundantly connected output assemblies, then communication between assemblies is enabled, but device complexity and wiring requirements increase
Solution Approach 1:
The patent merges the communication function into the existing power supply wiring by utilizing the power supply lines themselves for signal transmission. The second output assembly modulates its power supply voltage to encode diagnostic information, which the first output assembly detects during its diagnostic test, eliminating the need for separate communication wiring.
Solution Approach 2:
The power supply wiring serves dual purposes: it provides electrical power to the output assemblies and simultaneously acts as a communication channel for transmitting diagnostic information. This multi-functionality eliminates the need for dedicated communication cables while maintaining both power supply and data exchange capabilities.
2Reliability
If wire break identification is performed continuously in redundantly connected output assemblies, then detection capability is improved, but false alarms due to voltage fluctuations increase
Solution Approach 1:
The patent performs a preliminary diagnostic test by temporarily switching off the second output assembly before evaluating the current in the first output assembly. This preliminary action isolates the measurement to the first assembly's circuit, ensuring that any detected current flow is due to the first assembly's operation rather than voltage fluctuations or phantom signals from the second assembly.
Solution Approach 2:
The system uses feedback from the current measurement during the diagnostic test to verify whether a wire break actually exists. By measuring the current in the first output assembly during the switched-off period and comparing it against expected values, the system can confirm whether the initial diagnostic signal was a false alarm or indicates a real wire break condition.
Data Source
AI summary
A output assembly and method for diagnosing an electrical connection for reliably identifying a possible wire break to a load in redundantly connected output assemblies in which a control device for operating a switching device is configured such that the control device subjects the measured value to a test criterion, wherein satisfaction of the test criterion initially noted in the output assembly as a diagnosis fault, and the test criterion is applied cyclically within a time period comprising a waiting time, and wherein another output assembly performs a switch-off test during this time, thus allowing a statement to be made as to whether a wire break is present.