Galvanic Isolation Stage for Load Circuit Fault Detection
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Solution Overview
Problem
Conventional controllers cannot detect faults in the field side of an interface component, particularly when it is arranged in proximity to the controller, due to the long unmonitored cable section between the interface component and the field device, leading to inadequate fault detection in load circuits.
Innovation Solution
A device with an input part and an output part that converts switching commands from the controller into switching processes, includes a fault detection circuit to generate fault signals, and uses a galvanic isolation stage for isolated transmission of these signals, enabling evaluation of faults in the load circuit and ensuring line fault transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interface component is arranged in proximity to the controller, then the control side benefits from short cable connections, but the field side suffers from long unmonitored cable sections that cannot detect faults
Solution Approach 1:
The patent introduces an intermediary monitoring device positioned between the controller and the field device. This intermediary contains a control unit that generates test signals and a evaluation unit that detects faults, acting as a mediator that extends fault detection capability to the field side without requiring the controller itself to be complex. The intermediary converts switching commands into test signals and evaluates their return, enabling fault detection in the previously unmonitored cable section.
2Reliability
If conventional controllers directly connect to field devices, then the system structure is simple, but fault detection is limited to the control side only
Solution Approach 1:
The patent segments the control system into distinct functional units: the original controller, an intermediary monitoring device, and the field device. This segmentation allows the monitoring function to be separated from the control function, enabling line fault transparency on both sides independently. The intermediary device is divided into a control unit for signal generation and an evaluation unit for fault detection, allowing each segment to perform its specialized function efficiently.
3Reliability
If the controller monitors the entire cable length directly, then complete fault detection is achieved, but the controller complexity and load increase significantly
Solution Approach 1:
The intermediary monitoring device serves as a mediator that offloads the monitoring function from the controller. The control unit in the intermediary generates test signals and the evaluation unit detects faults, distributing the computational and electrical load away from the controller. This allows complete fault detection coverage without increasing controller load, as the intermediary handles all test signal generation and evaluation independently.
Data Source
AI summary
The invention relates to a device for monitoring and switching a load circuit, having an input part and an output part, having switching inputs to connect a controller to the input part, having switching outputs to connect at least one load circuit with at least one load to be switched to the output part, having at least one load switch to switch, in particular to switch on and off, the at least one load, having at least one fault detection circuit to detect a fault in the load circuit and to generate at least a first fault signal in the output part, and having a galvanic isolation stage for galvanically isolated transmission of this first fault signal and/or a second fault signal derived from this first fault signal from the output part to the input part. According to the invention the input part has an input circuit which converts switching commands of the controller incoming via the switching inputs into switching processes of the load switches. The transmitted fault signal is made available via the switching inputs for evaluation.