A Vortex Flowmeter Signal Processing System Based On Double-core Technique

Vortex flowmeters are widely used in different fields due to its high precision,simple structure and long using life. On the other hand, it is has poor performancewhen the process of low flow rate going along at which time the amplitude of constantnoises are comparatively stronger, or even submerge the useful signal. In this case, thetraditional method of analogue signal process is absolutely helpless. Therefore, it hasbecome one of the keystones of the signal process of the vortex flowmeter to researchhow to effectively analyze the character of vortex signal frequency-domain, pick upthe useful signal in the condition of low Signal-to-Noise.At present, many researches have done at home and abroad on solving thisproblem, but most of them still rest on theoretical period. There is little true use ofthese researching results into practice at home. This paper makes a deep research fromboth theoretical and practical aspects, and presents a digital signal processing systembased on double-core technique and Relaxing Notch Periodogram algorithm.Experimental results show that it can get good results in low flow rate measurementand realize practical application. The main work of this paper is shown as follows:1. Broken through traditional mode of single processor, adopt double-coretechnique combining TMS320VC5416 DSP with MSP430F149 MCU,enhanced the stability and real-time ability.2. Designed and realized a computer-based vortex signal processing system,enlarged low limit of vortex measurement, increased anti-interference anddemonstrated the high performance of Relaxing Notch Periodogram method.3. Using Relaxing Notch Periodogram method for reference, transplanting thisalgorithm into DSP, designed a digital vortex signal processing system. Thissystem realized the practical application of digital vortex flowmeter.Experimental results from Tianjin University flow laboratory and TianjinInstrument and Meter Plant show that this system can measure signal of 10Hz and therange scale can be up to 1:35. In the end, this system can expend the measurementlow limit, enlarge vortex measurement range and solve the accuracy, anti-interferenceproblems well, it fill-ups domestic blank and has great application value.