Vibratory Flowmeter Drive Signal Phase Alignment
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Solution Overview
Problem
Vibratory flowmeters, such as Coriolis mass flow meters, face challenges in generating drive signals that enable accurate and timely flow characteristics measurements, particularly in ensuring fast and reliable startup and diagnostic operations, while maintaining phase alignment with sensor signals.
Innovation Solution
The development of meter electronics that receive sensor signals, phase-shift them by 90 degrees, determine phase shift values, and combine these with squared signals to generate drive signals with identical phase and amplitude, ensuring the drive signal closely tracks the sensor signal phase and amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional drive signal generation method is used, then the flowmeter can operate, but the startup is slow and phase alignment with sensor signals is not maintained
Solution Approach 1:
The system performs preliminary action by pre-calculating and storing amplitude values in a lookup table before they are needed during operation. The amplitude table is populated with pre-computed values based on the relationship between frequency and amplitude, allowing the drive signal generator to immediately retrieve appropriate amplitude values during startup and operation, eliminating the need for real-time calculation and enabling fast, reliable startup.
Solution Approach 2:
The system uses copying by creating a lookup table that stores pre-computed amplitude values that replicate the relationship between frequency and amplitude. Instead of performing complex real-time calculations, the system copies the necessary amplitude information from the pre-populated table, maintaining phase alignment and operational accuracy while significantly reducing computational overhead and startup time.
2Measurement precision
If real-time phase calculation is performed, then phase alignment is maintained, but computational complexity and processing time increase
Solution Approach 1:
The system performs preliminary action by pre-calculating amplitude values and storing them in a lookup table before operation. The table is populated with amplitude values corresponding to different frequencies, allowing the system to maintain phase alignment precision by simply retrieving pre-computed values rather than performing complex real-time calculations, thereby reducing processing complexity while maintaining measurement precision.
Solution Approach 2:
The system uses copying by creating a lookup table that stores pre-computed amplitude information. Instead of performing complex real-time phase and amplitude calculations, the system copies the necessary values from the table, maintaining phase alignment precision while significantly reducing computational complexity and processing requirements.
3Measurement precision
If the drive signal frequency is changed to track resonance, then measurement accuracy improves, but the system becomes less stable under changing conditions
Solution Approach 1:
The system applies dynamics by making the drive signal frequency adjustable and adaptive. The frequency can be changed in response to changing operating conditions such as temperature variations or different fluid properties. The system dynamically selects the appropriate frequency from a range of available frequencies, allowing it to track resonance and maintain measurement accuracy while adapting to changing conditions rather than operating at a fixed frequency.
Solution Approach 2:
The system uses parameter changes by varying the drive signal frequency based on operating conditions. The frequency parameter is adjusted to track the resonance frequency of the flowtube, which changes with temperature and fluid properties. This allows the system to maintain measurement precision under varying conditions by changing the frequency parameter rather than maintaining a fixed frequency, thereby improving accuracy while maintaining stability through adaptive parameter adjustment.
Data Source
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AI summary
A meter electronics (20) for generating a drive signal for a vibratory flowmeter (5) is provided according to an embodiment of the invention. The meter electronics includes an interface (201) and a processing system (203). The processing system is configured to receive the sensor signal (201) through the interface, phase-shift the sensor signal (210) substantially 90 degrees to create a phase-shifted sensor signal, determine a phase shift value from a frequency response of the vibratory flowmeter, and combine the phase shift value with the sensor signal (201) and the phase-shifted sensor signal in order to generate a drive signal phase (213). The processing system is further configured to determine a sensor signal amplitude (214) from the sensor signal (210) and the phase-shifted sensor signal, and generate a drive signal amplitude (215) based on the sensor signal amplitude (214), wherein the drive signal phase (213) is substantially identical to a sensor signal phase (212).