CN201444056U

CN201444056U - Integral DSP digital VSF with high precision

Info

Publication number: CN201444056U
Application number: CN2008201781056U
Authority: CN
Inventors: 叶斌; 陈锋; 耿卫国; 刘帅; 李超
Original assignee: Beijing Aerospace Fengguang Electronic Technical Corp Ltd
Current assignee: Beijing Aerospace Fengguang Electronic Technical Corp Ltd
Priority date: 2008-11-20
Filing date: 2008-11-20
Publication date: 2010-04-28
Anticipated expiration: 2018-11-20

Abstract

The utility model applies DSP technology to a signal processing system of a VSF (vortex shedding flowmeter). The system comprises two modules including forward path signal conditioning and DSP signal processing, and consists of a charge amplifier circuit, a programmable amplifying circuit, a low-pass filter circuit, an A/D conversion circuit and a DSP basic system. A forward path converts piezoelectric signals output by the VSF into voltage signals through the charge amplifier circuit, and the signal processing module detects the basic frequency component in the signals, and outputs TTL level pulse signals having the same frequency with the frequency component, and 4-20 mA current signals. A self-detection signal generating circuit is added to the forward path signal conditioning module for detecting the system and improving the measurement precision. The system has four wire-jumping dial switches for further improving the flow measurement precision through adjusting parameters according to different flow ranges.

Description

The integrated DSP digital vortex shedding flowmeter of high precision

Technical field

The invention belongs to the flow measurement instrument field, is the integral intelligent instrument of the digital information processing system of core with DSP.

Technical background

Vortex flow sensors be with the generation of your vortex of toll bar and Strouhal and with the theory of discharge relation serve as according to the flow of measuring steam, gas and low-viscosity (mobile) liquid.Triangular prism of vertical insertion is a vortex generation body in the table body, has MEDIA FLOW out-of-date in the table body, alternately produces the opposite well-regulated toll bar vortex of direction in trequetrous back, and its vortex shedding frequency F is directly proportional with media flow speed V.Detect the number of vortex by sensing head, just can calculate rate of flow of fluid, calculate the volumetric flow rate of measured medium again according to table body bore.Vortex shedding flow meter have simple in structure firmly, be suitable for advantages such as type of fluid is many, precision is higher, rangeability is wide, crushing is little, if but its precision can further improve, range of application will further enlarge so.

Also there are some problems in present traditional vortex shedding flow meter, and is higher as the low discharge measurement lower limit, causes range ratio limited, and measurement range narrows down.And vortex shedding flow meter uses the field condition complexity, often causes the measurement pipeline vibration, disturbs the measurement result of vortex shedding flow meter, causes the vortex shedding flow meter measuring accuracy to descend or can't operate as normal.And when flow signal was unstable or faint, common vortex shedding flowmeter signal Processing Algorithm was difficult to reach accuracy requirement.

The TMS320VC5410 digital signal processor is a kind of in the TMS320VC54x series fixed DSP released of American TI Company, it has the LQFP encapsulation of 144 pins, adopt the I/O voltage of 3.3V and the core voltage power supply mode of 2.5V, have 3 independently multibus parallel organizations of 16 bit data bus and 1 program bus, its low-power consumption and be applicable to the exploitation of measurement instrument system at a high speed.

Selection high-performance digital signal processor and algorithm realize the accurate processing of vortex signal and at the different flow scope, especially the further optimization of primary flow signal has crucial meaning to the precision that improves vortex shedding flow meter.

Summary of the invention

The utility model mainly is made up of signal condition forward path and DSP signal processing module.Main passing through according to actual flow scope Adjustment System parameter and use Chirp-Z algorithm, measurement result under the faint situation of low discharge, pipeline vibration and flow signal of optimization vortex shedding flow meter, the situation of solve using vortex shedding flow meter measuring accuracy under the on-the-spot complex situations to descend or can't operate as normal, and the problem that reduces of the precision when solving low discharge and measuring.

Native system specifically comprises: charge amplifier circuit, programmable amplifying circuit, low-pass filter circuit, A/D change-over circuit and DSP ultimate system.The signal condition forward path is converted to voltage signal with the piezoelectric signal of vortex shedding flow meter output by charge amplifying circuit, and simultaneously, the sinusoidal signal about the generation 1000Hz of system is as self-test signal, and two paths of signals switches by analog switch.The output signal of analog switch is the input low-pass filter after programmable amplifier amplifies, the DSP signal processing subsystem utilizes A/D converter chip MAX1246 that low-pass filter output signal is gathered, by certain analysis, calculate dominant frequency component, and by Chirp-Z refinement analysis, obtain more accurate dominant frequency component, according to the dominant frequency component value, outwards output is with TTL pulse frequently and the 4-20mA current signal that is directly proportional with the pulsed frequency size.

The design self-test signal produces circuit, and the System self-test function is provided, and is used for the calibrating and test and the system calibration under standard signal of systemic-function when no input signal.Constitute sinusoidal oscillation circuit by amplifier and produce sinusoidal signal about 1000Hz, and between self-test signal and sensor signal, switch by analog switch.

There are four road wire jumper toggle switchs in system, has 16 kinds of gear settings, the pairing frequency range difference of different gears.Can be according to the scope Adjustment System parameter of actual flow velocity, to improve measuring accuracy.

The DSP signal processing subsystem is core with TMS320VC5410, and, comprising: power module, level translator, reset control module, JTAG socket, Logic control module, Flash memory, A/D conversion, D/A converter according to this type DSP design corresponding D SP as fired basis native system.

Design of System Software adopts interrupt mode, and flow process is shown in accompanying

drawing

5,6.

The beneficial effects of the utility model are that employing high-performance digital signal processor and algorithm are realized the accurate processing of vortex signal, at the different flow scope signal processing method are made corresponding modification, further improve the measuring accuracy of vortex shedding flow meter.

Description of drawings

Accompanying drawing 1: the utility model entire block diagram

Accompanying drawing 2: signal condition forward path circuit diagram

Accompanying drawing 3:DSP module principle figure

Accompanying drawing 4:4-20mA teletransmission circuit diagram

Accompanying drawing 5: main program flow chart

Accompanying drawing 6: interrupt service routine process flow diagram

Embodiment

Native system mainly is made up of signal condition forward path and DSP signal processing module, specifically comprises: charge amplifier circuit, programmable amplifying circuit, low-pass filter circuit, A/D change-over circuit and DSP ultimate system.The TMS320VC5410 that dsp chip adopts TI company to produce.The signal condition forward path is converted to voltage signal with the piezoelectric signal of vortex shedding flow meter output by charge amplifying circuit, simultaneously, sinusoidal signal about the generation 1000Hz of system is as self-test signal, and two paths of signals switches by single eight path analoging switch CD4051.The output signal of analog switch is imported the quadravalence low-pass filter after program control amplification, the DSP signal processing subsystem utilizes A/D converter chip MAX1246 that low-pass filter output signal is gathered.In addition, system adopts the Flash storer of the Am29LV200B 128KB of AMD's production that service data is stored.Adopt the GAL16LV8 chip of Lattice company to carry out the control of logic control and flash storer.System provides the operating voltage of 3.3V and the core voltage of 2.5V by the TPS767D325 power supply chip to the interface circuit of DSP.And, export the outside output of digital to analog converter AD421 with TTL pulse frequently and the 4～20mA current signal that is directly proportional with the pulsed frequency size by 16 bit serial input, 4～20mA current loop that U.S. ADI company produces according to the dominant frequency component value that DSP calculates.

After powering on, carry out the initialization of system, McBSP, DMA and interruption earlier, read in the toggle switch state then, and relevant parameter is set.Wait for look-at-me then, and enter interrupt handling routine, the analysis by certain calculates dominant frequency component, and analyzes by the Chirp-Z refinement, obtains more accurate dominant frequency component.Then control AD421, finish the output of 4～20mA current signal and pulse signal and wait for next time and interrupt.Master routine as shown in Figure 5, interrupt routine is as shown in Figure 6.

Claims

1. the integrated DSP digital vortex shedding flowmeter of high precision mainly is made up of signal condition forward path and DSP signal processing module, specifically comprises: charge amplifier circuit, programmable amplifying circuit, low-pass filter circuit, A/D change-over circuit and DSP ultimate system; It is characterized in that: the signal condition forward path is converted to voltage signal with the piezoelectric signal of vortex shedding flow meter probe output by charge amplifying circuit, simultaneously, sinusoidal signal about the generation 1000Hz of system is as self-test signal, and two paths of signals switches by analog switch; The output signal of analog switch is imported low-pass filter after program control amplification, the DSP signal processing subsystem utilizes A/D converter chip MAX1246 that low-pass filter output signal is gathered.

2. the integrated DSP digital vortex shedding flowmeter of high precision according to claim 1, it is characterized by: designed self-test signal and produced circuit, constitute sinusoidal oscillation circuit by amplifier and produce sinusoidal signal about 1000Hz, and between self-test signal and sensor signal, switch by analog switch.

3. the integrated DSP digital vortex shedding flowmeter of high precision according to claim 1 is characterized by: there are four road wire jumper toggle switchs in system, has 16 kinds of gear settings.

4. the integrated DSP digital vortex shedding flowmeter of high precision according to claim 1, it is characterized by: the DSP signal processing subsystem is a core with TMS320VC5410, comprising: power module, level translator, reset control module, JTAG socket, Logic control module, Flash memory, A/D conversion, D/A converter.