Synthetic Output Signal for Faster Fork Density Sensor Phase Control
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Solution Overview
Problem
Current vibratory sensors face delays in determining fluid properties due to the incremental approach required to reach off-resonant phase differences, which is time-consuming and inefficient, especially in applications where accuracy and speed are critical.
Innovation Solution
A method is introduced to control the vibration of a vibratory element based on phase errors by generating a synthetic time period (TPSig) output signal, which involves filtering and synthesizing the signal to measure phase differences and calculate vibration control terms, allowing for direct targeting of desired phase differences without the need for closed-loop feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a closed-loop circuit is used to incrementally approach target phase differences, then measurement accuracy is improved, but measurement time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the relationship between drive signal frequencies and resulting phase differences in a lookup table. This allows the system to directly retrieve the required frequency adjustment to achieve target phase differences (45° and 135°) without incremental trial-and-error, thus maintaining measurement accuracy while dramatically reducing the time required to determine fluid properties.
2Measurement precision
If incremental adjustment of drive frequency is used to reach target phase differences, then accurate phase difference measurement is achieved, but productivity decreases
Solution Approach 1:
The patent replaces the mechanical incremental adjustment process with a computational approach using a lookup table that stores pre-calculated frequency-phase relationships. This substitution eliminates the time-consuming mechanical tuning process while maintaining accurate phase difference measurement, thereby improving productivity without sacrificing measurement precision.
3Reliability
If closed-loop feedback control is implemented to achieve target phase differences, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent uses a lookup table that copies pre-stored frequency-phase relationship data to replace the need for complex real-time feedback control calculations. This copying approach maintains measurement reliability by ensuring consistent achievement of target phase differences while significantly reducing device complexity by eliminating sophisticated control circuitry in favor of a simple lookup and adjustment mechanism.
Data Source
AI summary
A system and method of generating a synthetic time period output signal for a fork density sensor (601) which produces a consistent and low-noise output signal (705) which is identical in frequency to the frequency at which the fork density meter vibrates. Such a synthetic signal generated by a meter signal prevents any real noise from the pickoffs from propagating to the output meter and removes process noise and interference from the produced output signal.