Signal Switching Assembly for Offset and Gain Error Detection
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Solution Overview
Problem
Existing circuit arrangements used in safety devices, particularly those meeting Safety Integrity Level 3, face challenges in reliably detecting faults such as line short circuits, component changes, and errors, which are crucial for ensuring high safety standards.
Innovation Solution
Incorporating a first switching device to selectively disconnect the input signal from the conditioning circuit and a second switching device to control the reference signal, allowing for the determination of offset and gain errors, enabling fault detection and calibration of the circuit arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If switching devices are added to enable fault detection and calibration, then measurement precision and reliability are improved, but device complexity increases
Solution Approach 1:
The switching assembly serves multiple functions: it enables both normal signal processing and fault detection/calibration operations through the same physical components. The first switching device selectively connects or disconnects the input signal from the conditioning circuit, while the second switching device controls reference signal injection, allowing a single circuit structure to perform both measurement and self-diagnosis functions.
Solution Approach 2:
The switching devices act as intermediaries that control the flow of signals between different circuit components. By selectively connecting or disconnecting the input signal and reference signal paths, the switching assembly mediates between the signal source and the conditioning circuit, enabling error detection without permanently altering the circuit structure.
2Reliability
If fault detection capabilities are implemented, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The circuit arrangement performs self-diagnosis by automatically detecting faults in its own components. The control device uses the switching assembly to isolate sections of the circuit and test them, allowing the system to self-monitor its health status without requiring external testing equipment or complex manual procedures.
Solution Approach 2:
The switching devices can be operated periodically to perform calibration and fault detection at scheduled intervals. The control device manages the switching sequence to alternately connect input signals and reference signals, enabling systematic error detection and correction cycles that maintain reliability without requiring continuous complex operations.
Data Source
Figure 1~2
AI summary
The invention relates to a circuit arrangement for evaluating an analog electrical signal with a control device, an input circuit for applying an input signal, a conditioning circuit electrically connected to the input circuit for converting the input signal into a measurement signal, an analog-to-digital converter electrically connected to the conditioning circuit for converting the measurement signal into a digital value, and a reference source that outputs a known reference signal.The system comprises a first switching device that selectively disconnects the input signal from or supplies it to the conditioning circuit, and a second switching device that selectively supplies or disconnects the reference signal from the input circuit, wherein the control device is configured to determine an offset error of the circuit arrangement when the input signal is disconnected from the conditioning circuit and the reference signal is not supplied to the input circuit, and to determine a gain error of the circuit arrangement when the input signal is disconnected from the conditioning circuit and the reference signal is supplied to the input circuit.