High temperature resistance digital two-wire system HART intelligent vortex flowmeter

Abstract

The invention relates to the flow detection field, and refers to a high temperature resistance digital two-wire system HART intelligent vortex flowmeter comprising a high temperature resistance vortex flow sensor, a first stage charge amplifier, a second stage charge amplifier, a first stage low pass filter, a second stage low pass filter, a voltage follower, a voltage-stabiliser tube, a digit power supply management circuit, a simulation power supply management circuit, an electric current loop and HART circuit, a digital isolation circuit, a one-chip microcomputer, a clock manager, a reset circuit, a power supply monitor, a keyboard, an LCD, and a temperature and pressure compensation unit. A signal conditioning circuit employs two-stage charge amplifiers and two-stage low pass filters to solve the problems that the high temperature resistance vortex flow sensor is low in sensitivity; two-path parallel power supplies respectively power up the simulation circuit and the digit circuit, thus solving the problems that the one-chip microcomputer is large in power consumption when doing FFT operation, yet the two-wire system HART intelligent vortex flowmeter requires the system consumed current is lower than 3.5mA. The high temperature resistance digital two-wire system HART intelligent vortex flowmeter can greatly improve measuring range ratio, measuring precision, and anti-interference capability.

Description

technical field [0001] The invention relates to the field of flow detection, and is a two-wire HART intelligent vortex flowmeter, in particular, a single-chip microcomputer (MCU) as the core, using FFT (Fast Fourier Transform) algorithm for vortex flow signal processing, using It is a high temperature resistant digital two-wire HART smart vortex flowmeter with a high temperature resistant vortex flow sensor made of materials with very good temperature characteristics, which has a small output signal amplitude and low sensitivity. Background technique [0002] In industrial applications, when the temperature of the measured medium is high or the temperature changes greatly, the ordinary vortex flowmeter has poor temperature characteristics of the vortex flow sensor. As the temperature rises, the measurement error of the flowmeter increases. bigger. Vortex flow sensors made of materials with very good temperature characteristics can work at high temperatures. However, the ou...

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Problems solved by technology

[0005] The technical scheme of the present invention is: adopt the signal conditioning circuit of two-stage charge amplifier plus two-stage low-pass filter, combined with the complete digital signal processing method; at the same time, shield the signal line and the signal conditioning circuit, reduce the electromagnetic radiation in the environment Interference, especially the influence of power frequency interference, solves the high-temperature-resistant vortex flow sensor made of materials with very good temperature characteristics due to the small output signal amplitude and low sensitivity. Problems such as low precision

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