Vortex shedding flowmeter based on CPLD and correcting method thereof

A vortex flowmeter, flow technology, applied in the direction of volume/mass flow caused by electromagnetic effect, volume/mass flow caused by mechanical effect, liquid/fluid solid measurement, etc., can solve the problem of program deviation from the normal path and narrow measurement range , unstable use and other problems, to achieve the effect of improved running speed, good real-time performance and fast running speed
CN101413814BInactive Publication Date: 2010-06-02TIANJIN UNIV
5 Cites 2 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
TIANJIN UNIV
Publication Date
2010-06-02
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention belongs to the technical field of flow measurement, and relates to a CPLD-based vortex shedding flowmeter. The vortex shedding flowmeter comprises a supply voltage conversion circuit, apiezoelectric sensor used for generated vortex shedding signals, a front end signal processing circuit, a standard pulse shaping circuit, the CPLD and a peripheral circuit thereof as well as a crystaloscillator circuit for providing a clock for the CPLD and a precision voltage flow conversion circuit, wherein, the piezoelectric sensor, the front end signal processing circuit and the standard pulse shaping circuit are sequentially connected, and PWM signals output from the standard pulse shaping circuit are sent to the CPLD; the CPLD stores a lookup table which reflects the corresponding relation between the vortex shedding frequencies before and after correction, and the CPLD counts the vortex shedding signals according to the input PWM signals, and corrects a count value by the lookup table to output a frequency signal reflecting the flow rate. The invention also provides a correction method of the flowmeter. The vortex shedding flowmeter and the correction method have the advantagesof low power consumption, reliable performance and good real-time property.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention belongs to the technical field of flow measurement, and in particular relates to a vortex flowmeter. Background technique

[0002] Flow sensors with frequency signal output such as vortex street and turbine can obtain output signals with good repeatability in a wide flow range. The instrument coefficient of the vortex flowmeter is basically a constant in the normal flow range, but it shows obvious nonlinearity when measuring small flow, which restricts the measurement range and measurement accuracy of the vortex flowmeter. For example, the general analog vortex street ensures that the range ratio can only reach 1:10 when the nonlinear error of the instrument coefficient is within ±1%, which is far lower than the theoretical range of 1:100. With the development and progress of industrial technology, the demand for wide-range and high-precision flow meters is becoming increasingly urgent, and various non-linear correction methods and appli...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More