Title :
Validation of vortex flowmeters
Author :
Clarke, D.W. ; Ghaoud, T.
Author_Institution :
Dept. of Eng., Oxford Univ., UK
Abstract :
A vortex-shedding flow meter produces an approximately sinewave signal whose average frequency is proportional to volumetric flow-rate. The frequency of vortex-shedding varies over a large range (up to 1:100), depending on the size of the flow meter. The conventional frequency-estimation method-a zero-crossing algorithm (ZC)-fails at low flows, where the signal:noise ratio is poor. This paper describes a dual phase-locked loop (DPLL) structure that tracks the frequency over the flow meter´s full range with improved accuracy. The lock indicators associated with each PLL provide the SEVA metrics.
Keywords :
calibration; flowmeters; frequency estimation; phase locked loops; SEVA metrics; average frequency; dual PLL structure; dual phase-locked loop structure; frequency tracking; lock indicators; sinewave signal; validation; volumetric flow-rate; vortex-shedding flow meter; vortex-shedding frequency-estimation method;
Conference_Titel :
Intelligent and Self-Validating Instruments -- Sensors and Actuators (Ref. No. 2001/179), IEE Seminar on
DOI :
10.1049/ic:20010216
