多功能数据采集仪的研制
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摘要
数据采集是现代测控系统的关键环节之一。常见的数据采集系统是为特定的功能需求而开发,每一通道上只能针对某一特定信号进行采集,通用性不强。基于这个问题,针对常见的工业控制场合的压力、流量、液位、位移、频率、温度、脉冲量、开关量等数据采集需求,综合PLC和无纸记录仪的优点,研制了一套多通道、高性能、通用型、便携式数据采集仪,在任何一个模拟通道上都可以实现对多种模拟信号的采集,以较低的成本最大程度地满足各种工业控制场合多通道、高精度的数据采集需求。
系统分为下位机数据采集板和上位机监控界面两部分,分别完成数据采集和数据显示的任务,两者通过通用串行接口协议(USS协议)和RS232/RS485总线进行通信。下位机数据采集板以内含24位A/D转换器的ADμC834芯片为核心,通过带隔离的两级模拟开关分别进行通道选择和功能选择,配合C语言编写的程序,完成模拟量和开关量的采集测量、数据发送和开关量的控制输出、噪声分析等功能。上位机监控界面利用C#.net语言和SQL Server 2005数据库进行开发,分析了系统的功能需求和用例模型,详细地描述了实验设置模块、操作显示模块、查询模块、噪声分析模块、滤波算法模块等模块的设计过程和所用控件。
对系统的硬件和软件部分进行了功能和性能调试,并进行了噪声分析。结果表明:该采集仪的功能强大,采集准确可靠,实时性好。它实现了8路全隔离的模拟量输入、12路全隔离的数字量输入、8路全隔离的数字量输出、两路PWM输出和一路4～20mA输出。在任何一个模拟量输入通道上都可以实现电压、电流、热电偶、电阻/热敏电阻、三/四线制热电阻等信号的采集;当采集任务改变时,只需重新设置采集命令。采集结果能够以曲线、表格等形式在上位机上实时显示,并具有噪声分析和精密测量功能。对于实时测量,利用Pt100传感器进行温度采集时,其采集精度达到±0.2℃,不确定度小于0.03℃;利用热电偶进行温度采集时,精度达到±0.5℃,不确定度小于0.08℃;对于电压、电流信号的采集,精度和不确定度都在0.3%以内;对于电阻/热电敏阻等信号的测量,精度和不确定度都在5%以内。精密测量的准确度更高。
该采集仪的精度高,成本低,小巧精致,具有很强的通用性和抗干扰性,具有广阔的市场前景。该采集仪已应用于实际的工业现场中,结果令人满意。
Data acquisition is one of the key sectors in modern measurement and control system. The data acquisition systems are usually designed for particular desire, their each channel only collect single kind of signals, thus their features are single and universality is not strong. Based on this issue, for the purpose of the pressure, flow, liquid level, displacement, frequency, temperature, pulse signals, switch signals data acquisition desire for industrial environment, synthesized the merits of PLC and paperless recording instrument, high performance, general-purpose and portable data acquisition instruments with multi-channels were fabricated. They can achieve multi-functional data acquisition on each analog input channel, and at the greatest extent to meet the multi-channel, high precision data collection desire of many kinds of industrial use.
The whole system contains a data acquisition board served as lower computer to achieve the mission of dada collection and a upper computer supervisory interface to accomplish the display of data which is from the lower computer on laptop/PC, and they communicate with each other through RS232/RS485 bus with Universal Serial Interface Protocol (USS Protocol).The board based on ADμC834 with 24-bit∑-△ADC embedded accomplishes the channel selection and function selection by two stages analog switches, which is collaborated with the program with C language to accomplish the functions of data collect of analog and digital signal, data send, the control and output of digital signal, the analysis of noise, and so on.The upper computer supervisory interface is developed by C#.net language and SQL Server 2005 database, its requirements and user case modules are analyzed, and its design produces of experiment setting module, operation and display module, requirement module, noise analysis module, filter algorithm are introduced in detail.
The functions and performance of hardware and software of this system are tested; noise analysis is done to verify its precision. The experimental results show that the systems have powerful functions, high accuracy, satisfying real-time. The acquisition instrument provides 8-channel analog input and 12-channel digital input and 8-channel digital output with full-isolated, and each analog input channel can achieve the signal collections of standard voltage, standard current, thermocouple, resistance/thermistor, 3-Wired/4–Wired RTD signal collection. When the collecting mission is changed, just need to set the corresponding collection command again. The real-time results of data collection can be displayed on laptop/PC in the form of graph and table, and possess the noise analysis function, accurate measurement function. For the real-time measurement, when Pt100 is used for temperature measurement, its precision reaches±0.2℃, its uncertainty degree is less than 0.03℃; when thermocouple is used for temperature measurement, its precision reaches±0.5℃, its uncertainty degree is less than 0.08℃; when voltage/current signal is used, its precision and uncertainty degree are less than 0.3%; when resistance/thermistor signal is used, its precision and uncertainty degree are less than 5%. Accurate measurement has higher precision and lower uncertainty.
The system has features of low cost, high precision, delicate and exquisite, strong anti-interference and universality, and has broad market prospects. The acquisition instruments have been used in actual industrial field with satisfactory results.
系统分为下位机数据采集板和上位机监控界面两部分,分别完成数据采集和数据显示的任务,两者通过通用串行接口协议(USS协议)和RS232/RS485总线进行通信。下位机数据采集板以内含24位A/D转换器的ADμC834芯片为核心,通过带隔离的两级模拟开关分别进行通道选择和功能选择,配合C语言编写的程序,完成模拟量和开关量的采集测量、数据发送和开关量的控制输出、噪声分析等功能。上位机监控界面利用C#.net语言和SQL Server 2005数据库进行开发,分析了系统的功能需求和用例模型,详细地描述了实验设置模块、操作显示模块、查询模块、噪声分析模块、滤波算法模块等模块的设计过程和所用控件。
对系统的硬件和软件部分进行了功能和性能调试,并进行了噪声分析。结果表明:该采集仪的功能强大,采集准确可靠,实时性好。它实现了8路全隔离的模拟量输入、12路全隔离的数字量输入、8路全隔离的数字量输出、两路PWM输出和一路4～20mA输出。在任何一个模拟量输入通道上都可以实现电压、电流、热电偶、电阻/热敏电阻、三/四线制热电阻等信号的采集;当采集任务改变时,只需重新设置采集命令。采集结果能够以曲线、表格等形式在上位机上实时显示,并具有噪声分析和精密测量功能。对于实时测量,利用Pt100传感器进行温度采集时,其采集精度达到±0.2℃,不确定度小于0.03℃;利用热电偶进行温度采集时,精度达到±0.5℃,不确定度小于0.08℃;对于电压、电流信号的采集,精度和不确定度都在0.3%以内;对于电阻/热电敏阻等信号的测量,精度和不确定度都在5%以内。精密测量的准确度更高。
该采集仪的精度高,成本低,小巧精致,具有很强的通用性和抗干扰性,具有广阔的市场前景。该采集仪已应用于实际的工业现场中,结果令人满意。
Data acquisition is one of the key sectors in modern measurement and control system. The data acquisition systems are usually designed for particular desire, their each channel only collect single kind of signals, thus their features are single and universality is not strong. Based on this issue, for the purpose of the pressure, flow, liquid level, displacement, frequency, temperature, pulse signals, switch signals data acquisition desire for industrial environment, synthesized the merits of PLC and paperless recording instrument, high performance, general-purpose and portable data acquisition instruments with multi-channels were fabricated. They can achieve multi-functional data acquisition on each analog input channel, and at the greatest extent to meet the multi-channel, high precision data collection desire of many kinds of industrial use.
The whole system contains a data acquisition board served as lower computer to achieve the mission of dada collection and a upper computer supervisory interface to accomplish the display of data which is from the lower computer on laptop/PC, and they communicate with each other through RS232/RS485 bus with Universal Serial Interface Protocol (USS Protocol).The board based on ADμC834 with 24-bit∑-△ADC embedded accomplishes the channel selection and function selection by two stages analog switches, which is collaborated with the program with C language to accomplish the functions of data collect of analog and digital signal, data send, the control and output of digital signal, the analysis of noise, and so on.The upper computer supervisory interface is developed by C#.net language and SQL Server 2005 database, its requirements and user case modules are analyzed, and its design produces of experiment setting module, operation and display module, requirement module, noise analysis module, filter algorithm are introduced in detail.
The functions and performance of hardware and software of this system are tested; noise analysis is done to verify its precision. The experimental results show that the systems have powerful functions, high accuracy, satisfying real-time. The acquisition instrument provides 8-channel analog input and 12-channel digital input and 8-channel digital output with full-isolated, and each analog input channel can achieve the signal collections of standard voltage, standard current, thermocouple, resistance/thermistor, 3-Wired/4–Wired RTD signal collection. When the collecting mission is changed, just need to set the corresponding collection command again. The real-time results of data collection can be displayed on laptop/PC in the form of graph and table, and possess the noise analysis function, accurate measurement function. For the real-time measurement, when Pt100 is used for temperature measurement, its precision reaches±0.2℃, its uncertainty degree is less than 0.03℃; when thermocouple is used for temperature measurement, its precision reaches±0.5℃, its uncertainty degree is less than 0.08℃; when voltage/current signal is used, its precision and uncertainty degree are less than 0.3%; when resistance/thermistor signal is used, its precision and uncertainty degree are less than 5%. Accurate measurement has higher precision and lower uncertainty.
The system has features of low cost, high precision, delicate and exquisite, strong anti-interference and universality, and has broad market prospects. The acquisition instruments have been used in actual industrial field with satisfactory results.
引文
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[2] Khasgiwale R, Krnan L, Perinkulam A, etc. Reconfigurable data acquisition system for weather radar applications. 48th Midwest Symposium on 7-10 Aug, 2005. Circuits and Systems: 822– 825.
[3]王琳,商周,王学伟.数据采集系统的发展与应用[J].电测与仪表, 2004 41(8): 4-9.
[4]陈烛夜.双通道并行多路数据采集卡的研究[D].苏州:苏州大学, 2007: 3-8.
[5]安捷伦公司.34980A多功能开关/测量主机及模块[EB/OL].[2008-12-18].http://www.home. agilent.com/agilent/product.jspx?nid=-35202.0.00&cc=CN&lc=chi.
[6] NI公司. NI最新推出10款Wi-Fi (无线)与以太网数据采集设备[EB/OL]. [2008-12-18].http://www.gongkong.com/Common/CompanyPage.aspx?Type=news&CompanyID=6-AB3C-99CBCD414E68&Id=2008082514553700001.
[7]横河公司. MX100数据采集系统[EB/OL]. [2008-12-18].http://www.yokogawa.com/cn/ns/ dac/cn-mx100_index.htm.
[8] Keithley Instruments Inc. Model 2001 High-Performance, 7-1/2-Digit DMM w/ 8k Memory. [EB/OL].[2008-12-18].http://www.keithley.com/products/dmm/?mn=2001.
[9]凌华科技.凌华发表全系列PCI Express数据采集卡[J].电子技术应用, 2007(08): 15.
[10]董超群,白涛. HOLLiAS-MACS系统在大亚湾核电站试验数据采集系统的应用[J].自动化博览, 2005(S2): 67-70.
[11] LIU Daming, LUO Jiarong, ZhAO Yanping etc. Development of Data Acquisition Card Driver for ICRH System on EAST. Plasma Sci. Technol, 2008,10(2): 240-244.
[12]张宇林,杨定礼,严石.基于LabVIEW的USB数据采集系统设计[J].微计算机信息, 2008, (31) :85-87.
[13] ZHANG Li, ZHONG Chong-quan,etc. Development of dynamic acquisition system of industrial field temperature data on WWW[J]. Journal of Dalian University of Technology, 44(06).
[14]吴佳.高性能数据采集系统设计与实现[D].长沙:国防科学技术大学, 2007. 1-8.
[15]侯永海,刘滨等.多功能数据采集仪[J].测控自动化, 2004, 20(3): 29-29.
[16]高迟,苏波等.基于DSP的便携式数据采集仪表[J].仪表技术, 2004(1): 34-35.
[17]郭俊杰.基于USB接口的多通道数据采集仪设计[J].兵工自动化,2007, 26(6): 85-88.
[18]宋华军,朱明,沈美丽.高精度数据采集仪的实现与研究[J].电子器件,2007, 30(1): 93-97.
[19]叶强, JHP2000高精度隔离数据采集器的研制[D].武汉:华中科技大学, 2004: 1-7.
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