Field Sensor Signal Verification Without Measurement Interruption
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Solution Overview
Problem
Existing field devices cannot output measured physical quantities while verifying their operational soundness, requiring removal from piping for verification, which disrupts continuous measurement operations.
Innovation Solution
A field device with a processor that verifies operational soundness by switching input between sensor and simulated signal, allowing output of measured values even during verification, using a simulated signal with a predetermined waveform to distinguish normal and abnormal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field device performs operational soundness verification by switching input to simulated signal, then verification accuracy is improved, but the ability to output measured physical quantities during verification deteriorates
Solution Approach 1:
The patent creates a copy of the measurement signal path by introducing a simulated signal generation circuit that produces test signals identical in form to actual measurement signals. This allows the verification process to use a copy (simulated signal) rather than the original (measurement signal), enabling verification without interrupting the original measurement function. The simulated signal serves as a duplicate test input that triggers verification while the system continues to output actual measured values.
2Ease of operation
If the field device is removed from piping for verification, then verification accessibility is improved, but operational continuity deteriorates
Solution Approach 1:
The field device performs self-verification by incorporating the simulated signal generation circuit and verification processing unit within its own structure. The device serves itself by generating test signals internally and processing them through its own converter and processor, eliminating the need for external verification equipment or device removal. This self-service capability allows verification to be performed in-situ without interrupting the measurement operation.
Solution Approach 2:
The system performs preliminary actions by continuously outputting the last valid measurement signal even during verification processes. Before verification fully engages, the system prepares to maintain measurement output by storing and readying previous measurement data, ensuring no gap in measurement output occurs when the verification process activates and switches to simulated signals.
3Duration of action of stationary object
If the field device outputs measured values during verification, then operational continuity is improved, but verification reliability deteriorates
Solution Approach 1:
The patent segments the signal processing into distinct functional paths: one path handles actual measurement signals for continuous output, while another path handles simulated verification signals. The processor distinguishes between these segments by recognizing when verification mode is active and separating the verification signal processing from normal measurement processing. This segmentation allows both functions to operate simultaneously without interference, maintaining verification reliability while ensuring measurement continuity.
Data Source
AI summary
A field device (10) includes a sensor (11) that measures a physical quantity and outputs a measurement signal indicating a measured value, converters (12, 15, 16) that perform a predetermined conversion process on the measurement signal, and a processor (17) that outputs an output signal corresponding to the measurement signal subjected to the conversion process. The processor (17) starts verifying operational soundness of the converters (12, 15, 16) when the measurement signal subjected to the conversion process satisfies a predetermined condition, and outputs, while the operational soundness of the converters (12, 15, 16) is being verified, a signal corresponding to the measurement signal subjected to the conversion process and acquired immediately before the operational soundness of the converters (12, 15, 16) is verified, or a signal corresponding to the measurement signal indicating a predetermined measured value of the sensor (11), as the output signal.