改进的低功耗、两线制数字涡街流量计软件研制
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摘要
将数字信号处理技术应用于涡街流量计的信号处理,可以有效地提高测量精度和扩展量程比。但是,数字信号处理算法一般要通过DSP来实现。由于DSP功耗大,无法满足有些工业现场对低功耗、两线制仪表的要求。而现有的低功耗、两线制仪表一般采用常规的信号处理方式,性能指标不好,例如,测量精度比较差,量程比小。
为此,我们课题组基于超低功耗单片机,采用数字频谱分析与模拟带通滤波器组相结合的方式,研制新型两线制数字涡街流量计。本文在软件方面对已有系统进行了很大的改进。通过用硬件定时器定时设标志、软件查询方式来实现各个功能模块的调度。用汇编语言编制FFT程序,并采用定点运算来减少运算量和存储量;采用对数据先判断再移位的方式,既防止计算结果的溢出,又保证足够的计算精度。采用多周期等精度方法测量涡街信号的频率,用标准时钟脉冲信号填充被测信号,保证测量精度。当相邻滤波器的频带有重叠时,根据其频带的交叉点来选择带通滤波器。在流量计算中,采用平均方法和加速方法,既保证了测量结果的重复性,又提高了响应速度。经过改进后的低功耗、两线制数字涡街流量计通过了实际流量的测试,并在工业现场稳定运行。
Digital signal processing technique is applied to the signal processing of vortex flowmeter for improving the measurement accuracy and extending the turn-down radio of vortex flowmeter effectively. The digital signal processing algorithms, however, are implemented by DSPs generally. It cannot meet the requirement of the low-power and two-wire meter due to the high power consumption of DSPs. The performance indexes of the existed vortex flowmeter with low-power and two-wire are not good, e.g. the measurement accuracy is low and turn-down ratio is small, because these meters adopted the conventional signal processing method.
In order to solve the aforementioned problems, our group developed a novel two-wire digital vortex flowmeter with a super low-power micro-controller, combining the digital spectrum analysis with the analog band-pass filters. This paper makes great improvement in the system software of the two-wire digital vortex flowmeter. The flags are set by the timer and checked by program to perform the call of the functional modules. The FFT program is developed with the assemble language, and the fixed-point calculation is employed to reduce the computational load and memory space of the algorithm. Before the data are shifted their values are checked first, which can avoid bit growth occurring and ensure the computation accuracy. The multi-period equal- precision measurement method is used to calculate the frequency of the vortex signal, and the measured signal is filled by the standard clock pulse signal to ensure the measurement accuracy. When the frequency bands of adjacent filters overlay, the band-pass filter is selected according to the junction of the frequency band. Averaging and accelerating methods are adopted in flow calculation to ensure the repeatability and reduce the response time. This system has passed the flow tests, and runs normally in the industrial field.
为此,我们课题组基于超低功耗单片机,采用数字频谱分析与模拟带通滤波器组相结合的方式,研制新型两线制数字涡街流量计。本文在软件方面对已有系统进行了很大的改进。通过用硬件定时器定时设标志、软件查询方式来实现各个功能模块的调度。用汇编语言编制FFT程序,并采用定点运算来减少运算量和存储量;采用对数据先判断再移位的方式,既防止计算结果的溢出,又保证足够的计算精度。采用多周期等精度方法测量涡街信号的频率,用标准时钟脉冲信号填充被测信号,保证测量精度。当相邻滤波器的频带有重叠时,根据其频带的交叉点来选择带通滤波器。在流量计算中,采用平均方法和加速方法,既保证了测量结果的重复性,又提高了响应速度。经过改进后的低功耗、两线制数字涡街流量计通过了实际流量的测试,并在工业现场稳定运行。
Digital signal processing technique is applied to the signal processing of vortex flowmeter for improving the measurement accuracy and extending the turn-down radio of vortex flowmeter effectively. The digital signal processing algorithms, however, are implemented by DSPs generally. It cannot meet the requirement of the low-power and two-wire meter due to the high power consumption of DSPs. The performance indexes of the existed vortex flowmeter with low-power and two-wire are not good, e.g. the measurement accuracy is low and turn-down ratio is small, because these meters adopted the conventional signal processing method.
In order to solve the aforementioned problems, our group developed a novel two-wire digital vortex flowmeter with a super low-power micro-controller, combining the digital spectrum analysis with the analog band-pass filters. This paper makes great improvement in the system software of the two-wire digital vortex flowmeter. The flags are set by the timer and checked by program to perform the call of the functional modules. The FFT program is developed with the assemble language, and the fixed-point calculation is employed to reduce the computational load and memory space of the algorithm. Before the data are shifted their values are checked first, which can avoid bit growth occurring and ensure the computation accuracy. The multi-period equal- precision measurement method is used to calculate the frequency of the vortex signal, and the measured signal is filled by the standard clock pulse signal to ensure the measurement accuracy. When the frequency bands of adjacent filters overlay, the band-pass filter is selected according to the junction of the frequency band. Averaging and accelerating methods are adopted in flow calculation to ensure the repeatability and reduce the response time. This system has passed the flow tests, and runs normally in the industrial field.
引文
[1] J . J . Miau , C. C. Hu , J . H. Chou , Response of a vortexflowmeter to impulsive vibrations , Flow Measurement and instrument , 2000 ,11 :41～49
[2] Bernhard Menz, Vortex flowmeter with enhanced accuracy and reliability by means of sensor fusion and self-validation, Journal of the International Measurement Confederation, 1997, v22: 123~128
[3] Lowell A. Kleven , et al. Rapid transfer function determination for a tracking filter. US5942696 ,1999 ,8
[4] Wada Masami, Hondo Masanori, Ando Tetsuo, Vortex Flowmeter, JP2001153698,08 June 2001
[5] Warren E, Adaptive Filter with Sweep Filter Analyzer for a Vortex Flowmeter,US6212975B1,Apr.10,2001
[6] James H.Vignos, M.Charles Cheney et al,Adaptive Filtering for a Vortex Flowmeter,US5576497,Nov.19,1996
[7] Masanori Hondoh, Masami Wada, et al. A vortex flowmeter with spectral analysis signal processing, Sicon’01 Sensors for Industry Conference,2002,12
[8]姜仲霞等.涡街流量计现场应用的干扰与对策.自动化仪表, 1992,13(8):31-36
[9]徐科军,吕迅竑,陈荣保等.涡街流量计数字信号处理系统,中国发明专利,专利号:ZL99101209.7,申请日:1999.1.8,授权公告日:2003.4.2
[10]徐科军,吕迅竑,陈荣保等.基于DSP具有谱分析功能的涡街流量计信号处理系统,仪器仪表学报,2001,22(3):255-260
[11]徐科军,汪安民.涡街流量计信号估计的自适应陷波方法,仪器仪表学报,2000,21(2):222~224.
[12]徐科军,汪安民.基于小波变换的涡街流量计信号处理方法,仪器仪表学报,2000,22(6):636~639.
[13]徐科军,黄云志.强干扰下涡街流量计信号处理方法的研究,电子测量与仪表学报,2000(增刊):437~440
[14]徐科军,汪安民.涡街质量流量计的一种信号处理方法,山东工业大学学报,1999,34(3A):221~223.
[15]李永三,徐科军.涡街流量计信号处理方法研究与系统设计,合肥工业大学学报,2002,25(6):1130-1134
[16] Ke-Jun Xu, An-Min Wang and Xun-Hong Lv. Adaptive Notch Filter– based Signal Processing Method and System for Vortex Flowmeter,Review ofScientific Instruments,2001,72(4):2219-2220
[17]蒙建波,朱林章.自适应频率测量方法(AMF)在涡街流量计中的应用,自动化学报,1992,18(3):362-366
[18]王肖芬,徐科军,陈智渊.基于DSP的低成本涡街流量计信号处理系统,仪器仪表学报,2006,27(11):1427-1432
[19]王肖芬.涡街流量计数字信号处理和传感器动态非线性建模,合肥工业大学硕士学位论文,2004
[20]陈智渊.若干基于DSP与MCU的应用系统硬件研制,合肥工业大学硕士学位论文,2005
[21]张涛,段瑞峰.低功耗数字式涡街流量计,中国专利,申请号:200410019008.9,申请日:2004.4.14
[22]杜清府.压电晶体式涡街流量传感器放大电路的设计,自动化仪表,2005,26(3):52-54
[23]许剑,卢建刚.基于MSP430F449的新型智能流量计的设计与开发,自动化与仪器仪表,2005,第4期:27-32
[24]黄丹,陈昕,周康源.利用MSP430芯片实现小波变换对涡街信号的去噪测量,数据采集与处理,2004,19(1):37-40
[25]莫德举,孙丽.低功耗多变量涡街变送器的研究,仪器仪表学报,2002,第23卷第3期增刊:860-862
[26]陈荣保,王谊.基于MSP430的低功耗涡街流量计,自动化仪表,2003,24(11):26-28
[27]胡海清,陈章位.低功耗只能涡街流量计的设计,机电工程,2006, 23(11):29-35
[28]徐科军,曾宪俊等.低功耗两线制涡街流量计,中国专利,申请号:200710162074.5,申请日:20007.11.14
[29]沈建华,杨艳琴,翟骁曙.《MSP430系列16位超低功耗单片机原理与应用》,北京:清华大学出版社,2004
[30] Texas Instruments,MSP430x15x, MSP430x16x, MSP430x161x MIXED SIGNAL MICROCONTROLLER,DATASHEET,2002
[31] Texas Instruments,MSP430x1xx Family,User’s Guide,2006
[32] Texas Instruments,TPS62050, TPS62051,TPS62052, TPS62054, TPS62056,DATASHEET,2002
[33] Texas Instruments,XTR115,XTR116,DATASHEET,2000
[34] ON Semiconductor,LP2950, LP2951, NCV2951 DATASHEET,2005
[35] ANALOG DEVICES,Dual 256-Position SPI Digital Potentiometer AD5162,DATASHEET,2003
[2] Bernhard Menz, Vortex flowmeter with enhanced accuracy and reliability by means of sensor fusion and self-validation, Journal of the International Measurement Confederation, 1997, v22: 123~128
[3] Lowell A. Kleven , et al. Rapid transfer function determination for a tracking filter. US5942696 ,1999 ,8
[4] Wada Masami, Hondo Masanori, Ando Tetsuo, Vortex Flowmeter, JP2001153698,08 June 2001
[5] Warren E, Adaptive Filter with Sweep Filter Analyzer for a Vortex Flowmeter,US6212975B1,Apr.10,2001
[6] James H.Vignos, M.Charles Cheney et al,Adaptive Filtering for a Vortex Flowmeter,US5576497,Nov.19,1996
[7] Masanori Hondoh, Masami Wada, et al. A vortex flowmeter with spectral analysis signal processing, Sicon’01 Sensors for Industry Conference,2002,12
[8]姜仲霞等.涡街流量计现场应用的干扰与对策.自动化仪表, 1992,13(8):31-36
[9]徐科军,吕迅竑,陈荣保等.涡街流量计数字信号处理系统,中国发明专利,专利号:ZL99101209.7,申请日:1999.1.8,授权公告日:2003.4.2
[10]徐科军,吕迅竑,陈荣保等.基于DSP具有谱分析功能的涡街流量计信号处理系统,仪器仪表学报,2001,22(3):255-260
[11]徐科军,汪安民.涡街流量计信号估计的自适应陷波方法,仪器仪表学报,2000,21(2):222~224.
[12]徐科军,汪安民.基于小波变换的涡街流量计信号处理方法,仪器仪表学报,2000,22(6):636~639.
[13]徐科军,黄云志.强干扰下涡街流量计信号处理方法的研究,电子测量与仪表学报,2000(增刊):437~440
[14]徐科军,汪安民.涡街质量流量计的一种信号处理方法,山东工业大学学报,1999,34(3A):221~223.
[15]李永三,徐科军.涡街流量计信号处理方法研究与系统设计,合肥工业大学学报,2002,25(6):1130-1134
[16] Ke-Jun Xu, An-Min Wang and Xun-Hong Lv. Adaptive Notch Filter– based Signal Processing Method and System for Vortex Flowmeter,Review ofScientific Instruments,2001,72(4):2219-2220
[17]蒙建波,朱林章.自适应频率测量方法(AMF)在涡街流量计中的应用,自动化学报,1992,18(3):362-366
[18]王肖芬,徐科军,陈智渊.基于DSP的低成本涡街流量计信号处理系统,仪器仪表学报,2006,27(11):1427-1432
[19]王肖芬.涡街流量计数字信号处理和传感器动态非线性建模,合肥工业大学硕士学位论文,2004
[20]陈智渊.若干基于DSP与MCU的应用系统硬件研制,合肥工业大学硕士学位论文,2005
[21]张涛,段瑞峰.低功耗数字式涡街流量计,中国专利,申请号:200410019008.9,申请日:2004.4.14
[22]杜清府.压电晶体式涡街流量传感器放大电路的设计,自动化仪表,2005,26(3):52-54
[23]许剑,卢建刚.基于MSP430F449的新型智能流量计的设计与开发,自动化与仪器仪表,2005,第4期:27-32
[24]黄丹,陈昕,周康源.利用MSP430芯片实现小波变换对涡街信号的去噪测量,数据采集与处理,2004,19(1):37-40
[25]莫德举,孙丽.低功耗多变量涡街变送器的研究,仪器仪表学报,2002,第23卷第3期增刊:860-862
[26]陈荣保,王谊.基于MSP430的低功耗涡街流量计,自动化仪表,2003,24(11):26-28
[27]胡海清,陈章位.低功耗只能涡街流量计的设计,机电工程,2006, 23(11):29-35
[28]徐科军,曾宪俊等.低功耗两线制涡街流量计,中国专利,申请号:200710162074.5,申请日:20007.11.14
[29]沈建华,杨艳琴,翟骁曙.《MSP430系列16位超低功耗单片机原理与应用》,北京:清华大学出版社,2004
[30] Texas Instruments,MSP430x15x, MSP430x16x, MSP430x161x MIXED SIGNAL MICROCONTROLLER,DATASHEET,2002
[31] Texas Instruments,MSP430x1xx Family,User’s Guide,2006
[32] Texas Instruments,TPS62050, TPS62051,TPS62052, TPS62054, TPS62056,DATASHEET,2002
[33] Texas Instruments,XTR115,XTR116,DATASHEET,2000
[34] ON Semiconductor,LP2950, LP2951, NCV2951 DATASHEET,2005
[35] ANALOG DEVICES,Dual 256-Position SPI Digital Potentiometer AD5162,DATASHEET,2003