Redundant Current Measurement with Voltage Gradient Monitoring
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Solution Overview
Problem
Existing redundant current measurement systems in automation systems face challenges in quickly detecting and responding to one-sided wire breaks, leading to measurement errors and potential misinterpretations, particularly in systems using parallel connections of active and passive input channels.
Innovation Solution
A measuring arrangement with at least two current measuring modules connected in parallel, each with an analog input and a current measuring resistor, along with a control unit that monitors voltage gradients to quickly identify opposite direction changes, allowing for swift exclusion of the affected module and maintaining accurate current measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two active input channels are connected in parallel to increase availability, then redundancy is improved, but measurement precision deteriorates due to current distribution and interpretation complexity
Solution Approach 1:
The patent divides the current measurement task into two separate measurement channels, each with its own current-to-voltage conversion circuit. Instead of sharing a single measurement path, the system segments the measurement function across parallel independent channels, allowing each channel to measure the full current independently without current distribution issues.
Solution Approach 2:
The patent introduces voltage measurement as an intermediary step between current measurement and evaluation. By converting current to voltage in each channel and then comparing the voltage values, the system avoids direct current interpretation complexity while maintaining measurement accuracy through the voltage intermediary.
2Device complexity
If parallel connection of active and passive input channels is used, then device complexity is reduced, but reliability deteriorates because only the active channel can detect wire breaks
Solution Approach 1:
The patent merges the advantages of both active and passive channels by making both channels active with identical measurement capabilities. Both channels perform current-to-voltage conversion and can independently detect wire breaks, combining the simplicity of passive channels with the detection capability of active channels.
Solution Approach 2:
The patent implements a feedback mechanism where both channels continuously monitor their own voltage outputs and compare them. When a wire break occurs in one channel, the voltage comparison provides immediate feedback to detect the discrepancy, enabling reliable wire break detection while maintaining simple parallel channel configuration.
3Measurement precision
If series connection of analog inputs is used, then measurement precision is maintained, but device complexity increases due to isolation requirements and external wiring
Solution Approach 1:
Instead of connecting inputs in series as in conventional approaches, the patent inverts the connection topology by using parallel connection. This inversion allows both channels to see the full current independently while maintaining measurement precision through voltage comparison, eliminating the need for complex series wiring and isolation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid detection and response to wire breaks, minimizing temporary measurement errors and ensuring accurate current measurement by excluding the affected module, thus preventing false data transmission to higher-level automation systems.
Implementation Method 1
each with an analog input and a current measuring resistor, along with a control unit that monitors voltage gradients
Data Source
AI summary
Proposed is a measuring arrangement for the redundant determination of a quantitative value of a current flow, wherein the measuring arrangement has at least one first current-measuring module and at least one second current-measuring module connected in parallel with the first current measuring module, the first current-measuring module comprising at least one first analogue input and at least one first current measurement resistor and an associated voltage-measuring unit, in order to determine a current value of a current flowing into the analogue input and through the first current measurement resistor, the second current measuring module comprising at least one second analogue input and at least one second current measurement resistor and an associated voltage-measuring unit, in order to determine a current value of a current flowing into the second analogue input and through the second current measurement resistor. The measuring arrangement is characterised in that it comprises a control unit, which is designed and provided to detect a gradual change in the voltages determined by the voltage-measuring units, and in the event of gradual changes in the voltages that are counter to each other, a current-measuring module is excluded from a determination of the quantitative value of the current flow.