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A method of counting pulse type vortex flowmeter test

by:Sincerity     2021-01-08
Because the vortex flow meter has high measurement precision, wide range measurement medium widely, high working temperature, Medium temperature can reach 350 ℃) , corrosion resistance and high reliability characteristics, widely used in petroleum, chemical industry, light industry and heating power pipeline medium ( Such as gas, liquid and steam, etc. ) Measurement of fluid flow, a variety of media. General vortex flowmeter measurement more steam, water and other medium, such as thermal power plant power generation will produce steam, the steam can be used and production and reuse, so thermal power plant can foreign sell steam. So you want to install flowmeter to measure how much steam output to the user, which is to measure the flow of steam, so the measurement must be accurate. Vortex street flowmeter test results of the analog signal, also have a digital pulse signal output, and pulse type vortex flowmeter test results in pulse output, the traditional measurement method using filter after filtering by the number of counters to measure the pulse, thus the flow is calculated. But this way only measuring pulse number of pulses appear abnormal situation ( Such as equipment failure or human factors) Unable to distinguish, more can't feedback in time. The abnormal pulse will lead to inaccurate flow metering, ZUI will directly affect the interests of both sides. So urgently need a new kind of method, not only can accurately measuring pulse number, and when the abnormal condition pulse can also be found in a timely manner. 1. Test method of pulse type vortex flowmeter counts detection method using A/D sampling, cooperate with software processing method of pulse counting and discrimination. Using high speed A/D acquisition pulse input port of the voltage amplitude and mean filtering software according to the collected results after statistical pulse number; Will be a period of time to collect the voltage amplitude and mean and when installed at the beginning of vortex street flowmeter ZUI, comparing the normal voltage amplitude and mean to determine pulse output voltage is normal; Save a year of measurement data, and each measurement results compared with the same period a year ago, the pulse number. Through the voltage value and the dosage of comprehensive contrast, judge whether the vortex street flowmeter output is normal. 2. Profile 2. 1 hardware scheme in order to complete the pulse measurement and detection, must have certain hardware as support. The method of detection device is shown in figure 1, as shown in the dashed part by the filter circuit, power supply module, a storage unit, clock, remote communication module, man-machine interface and ARM. Passive filter circuit, filter circuit mainly filter out interference signal, the output voltage ripple coefficient is reduced, improve the detection accuracy. Power supply module USES multiple sets of power supply for the whole detection device work, pay special attention to is to give A/D acquisition power supply is 1% accuracy of the power supply, to ensure that the acquisition precision. Ferroelectric memory and Flash storage module USES a combination of. Because you want to store a year of traffic data, the data quantity is very large. And sampling data real-time acquisition, real time, reading and writing are quite frequent. Flash space is large, but the number of read and write is limited; Ferroelectric, speaking, reading and writing speed is quick, but more capacity is small. So with the method of combination of Flash and ferroelectric, real-time data in ferroelectric, first time to transfer data in ferroelectric to Flash. Clock unit need to bring your own battery, prevent terminal clock error when the power is cut off. Remote communication module is used for information interaction with data center, the test results and exception information transmitted to the data center in a timely manner. The human-computer interaction interface is used for displaying and setting up the scene. The CPU is a 32-bit ARM hardware platform, with 12 bita/D acquisition, acquisition time 51 us. After collecting junction east CPU for integrated processing of the collected data. 2. 2 software solutions software main process as shown in figure 2, system initialization, mainly for data collection, pulse counting and pulse testing cycle. 2. 2. 1 sampling data of five us 1 points, 10 points collected after removal of a ZUI great value and a small ZUI, then calculate the average. Acquisition value & le; ( 0. 3 x benchmark pulse amplitude) , 1; Acquisition value & ge; ( 0. 7 x benchmark pulse amplitude) , 2; Otherwise 0. The time required for a valid data of 10 & times; 5 us = 50 us, 1 s can be collected 20000 valid data. Every minute of the above testing voltage value of 2 average calculation of pulse amplitude, to all take an average of calculating the average pulse voltage value, after completion of installation and debugging are kept pulse amplitude and mean value. 2. 2. 2 for 1 s pulse counting, due to the time of data processing, and the vortex street flowmeter output pulse cycle may not be consistent. Collect some pulse may be truncated when every second, and in order to avoid less pulse, need to deal with pulse. Will be on for a second ZUI after a period of 2 consecutive Numbers and all Numbers after a merger with the data, to deal with. To avoid much plan the pulse of the ZUI after a period of continuous 2 and after all the figures don't do processing, until the next second. Pulse count, traversing the data records, identify and record each consecutive number of Numbers in section 2 to 2 and the whole data record for 2 Numbers to the total number of segments; Take out a piece of data, remember to benchmarks, by a number of other data segment number 2, compared with that of two digit number 2 difference within three of the total number of segments, and then use every piece of data as a benchmark contrast paragraphs, repeat the operation; Find the number of difference within three ZUI much data section, first of all, with all the difference in this paragraph 3 within the data segment is an effective pulse, and the number of the data in paragraph 2 do on average, the average number as a benchmark to calculate pulse cycle, and then can not meet the needs of difference of 3 data for processing.
are important in ensuring endress hauser ultrasonic flow meter, and the machine is utilised by everyone from rosemount vortex flow meter to insertion ultrasonic flow meter.
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Beijing Sincerity Automatic Equipment Co., Ltd harnesses science and technology to create products that support safer and healthier living and that enhance the overall quality of life.
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