多通道农药残留检测系统设计
摘要
食品安全直接关系到人们的生命健康,影响人们的生活质量,食品安全问题一直是受全世界广泛关注的重大问题。目前在中国,食品的农药残留仍是食品安全最主要的影响因素,随着国家质检总局颁布了《蔬菜中有机磷和氨基甲酸酯类农药残留量快速检测》GB/T5009.199-2003国家标准,市场对食品分析检测仪器的需求也越来越迫切。
本文利用酶抑制率—紫外及可见分光光度法,制造一种多通道的农药残留快速检测系统,通过检测农药残留对生物酶的抑制率确定农药残留的程度。系统采用了多路发光二极管为光源,该仪器可以实现样品的多路检测,并使检测结果通过由单片机组成的数字系统实现数据的精确处理。单片机采用了新型的C8051F系列SOC(片上系统),提高了系统的集成度,检测结果将被显示在液晶显示器上,液晶显示器同时完成控制菜单和数据输出显示,不易产生视觉错误和误读范围的错误;另外配有4*5键盘使操作更方便,简单;微型打印机使用户可以方便地打印检测结果;系统还包括可长期保存数据的EEPROM存储器。该研究将光电技术、传感技术、微电子技术、微机械学技术、计算机技术和食品安全检测技术融为一体,具有准确、灵敏、快速、简便、智能化等特点。
Pesticide residues in our food is a serious problem threatening people's daily life. A multi-channel detection system for pesticide residues based on C8051F MCU is designed in this paper. Unlike the traditional method of which only one sample solution can be detected at the same time, this instrument detects 96 solutions every time. Optical, mechanical and electronic integration enormously enhances the efficiency and the accuracy.
This system works on base of the theory that absorption law in spectroanalysis. Absorbency analyzing theory is also called Ultraviolet-visible Spectrophotometry, UV-Vis which is based on speciality and extent of absorbency for substance molecule, a method to quantitative analysis.
In another hand, under a certain condition pesticide of organophosphorus carbamate and cholinesterase have a special biochemical reaction: after the hydrolysis of cholinesterase, products of the hydrolysis react with a certain chromogenic reagent, the color changes after the reaction. But the reaction is affected by the pesticide of organophosphorus carbamate, they can restrain the reaction and the color will not change. The inhibitory rate is correlated with the concentration of pesticide positively. The system can judge the degree of the pesticide of organophosphorus carbamate in the samples by detecting the inhibitory rate.
The working process is: the monochromatic light generating from the LED goes through the solution which is put into an 8*12 holes test-tube moved by a step-motor and shoots to silicon photocells. The photocells convert the light signal to current signal. The current signal is transported to a amplifier circuit and is changed into voltage signal which is subsequently received by A/D converter of a MCU. The MCU is in charge of controlling the step-motor, display, communication and data processing.
The system uses C8051020F device as its MCU. The C8051F020 family utilizes Silicon Labs' proprietary CIP-51 microcontroller core. The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute with a maximum system clock of 12-to-24 MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with only four instructions taking more than four system clock cycles.
The most unique enhancement is the Digital Crossbar. The on-chip counter/timers, serial buses, HW interrupts, ADC Start of Conversion input, comparator outputs, and other digital signals in the controller can be configured to appear on the Port I/O pins specified in the Crossbar control registers.
The C8051F020 has an on-chip 12-bit SAR ADC (ADCO) with a 9-channel input multiplexer and programmable gain amplifier. With a maximum throughput of 100ksps, the ADC offers true 12-bit accuracy. The internal voltage reference circuit consists of a 1.2 V, 15 ppm/℃(typical) bandgap voltage reference generator and a gain-of-two output buffer amplifier. So using the internal voltage requires that the input current must be lower than 2.4V.
Eight light-emitting diodes are used as light source of which light shoots to the solutions. A voltage stabilizer LM317 supplies a stable voltage to the diodes. During the course of measuring, diodes should be lighted one by one so as not to cause interference to adjacent ones. As a result a decoder 74LS138 is used. Since the output current of 74LS138 is not enough to light the diodes, two power transistors 9013 are connected to a diode.
The acquisition circuit is composed of eight silicon photocells and an analog multiplexer CD4051. The current signal emitted by the photocell is so weak that the MCU can not detect exactly. So the output of CD4051 is connected to the input of an amplifier circuit. The amplifier circuit contains a low-pass filter and an integrated operational amplifier OP07. The out voltage from the amplifier circuit and the signal ground are connected to the differential input ports of a instrumentation amplifier AD623 which is configured for unity gain (G = 1) in order to eliminate the common-mode interference.
The system equips a four-phase inductor 47BYGH107 type step-motor. Its driving circuit has four triodes TIP122 and four diodes IN4003. It makes multi-detecting possible and the number in one time detecting can be 96.
The system employs a LCM240128 made by XINHUALONG Corp. to display the result. The module contains LCD display, driving circuit, controlling module T6963C made by TOSHIBA,PCB main board ,RAM, and backup light.
A 4*5 matrix keyboard is used and its nine controlling lines are all linked to the I/O ports of the MCU.
The system has the capability of storing 1000 results by using a EEPROM AT24C512 even when it is not powered. The SMBus0 I/O interface between AT24C512 and MCU is a two-wire, bi-directional serial bus. It is compatible withthe I~2C serial bus.
It is convenient for users to confirm and record the time by using a real time clock chip SD2303. In this system users could get or modify the time at any time. The interface between SD2303 to MCU is also a two-wire serial bus.
A serial printer made by WEIDA is used. It makes that the result can not only be stored in the EEPROM, but also be printed out for people to check out.
The system employs a portable switch power. Other internal voltages can be got by using some DC-DC converters.
The system is programmed with C language under the development environment of Keil C uVision 2. Modularized programs consist of: multi-chinese character menu, displaying and modifying time, measuring and storing the result, querying and printing the history data and connecting to PC.
To validate the dependability and stability of the whole system, a common kind of fast measuring reagent for pesticide residues is used to detect the samples. The result is satisfied, the whole system is succeeded.
The whole system performed well in the experiment. We should developed it and make more advantage. An improved system can distinguish the kind of a pesticide and also quantitative analysis can be realized.
本文利用酶抑制率—紫外及可见分光光度法,制造一种多通道的农药残留快速检测系统,通过检测农药残留对生物酶的抑制率确定农药残留的程度。系统采用了多路发光二极管为光源,该仪器可以实现样品的多路检测,并使检测结果通过由单片机组成的数字系统实现数据的精确处理。单片机采用了新型的C8051F系列SOC(片上系统),提高了系统的集成度,检测结果将被显示在液晶显示器上,液晶显示器同时完成控制菜单和数据输出显示,不易产生视觉错误和误读范围的错误;另外配有4*5键盘使操作更方便,简单;微型打印机使用户可以方便地打印检测结果;系统还包括可长期保存数据的EEPROM存储器。该研究将光电技术、传感技术、微电子技术、微机械学技术、计算机技术和食品安全检测技术融为一体,具有准确、灵敏、快速、简便、智能化等特点。
Pesticide residues in our food is a serious problem threatening people's daily life. A multi-channel detection system for pesticide residues based on C8051F MCU is designed in this paper. Unlike the traditional method of which only one sample solution can be detected at the same time, this instrument detects 96 solutions every time. Optical, mechanical and electronic integration enormously enhances the efficiency and the accuracy.
This system works on base of the theory that absorption law in spectroanalysis. Absorbency analyzing theory is also called Ultraviolet-visible Spectrophotometry, UV-Vis which is based on speciality and extent of absorbency for substance molecule, a method to quantitative analysis.
In another hand, under a certain condition pesticide of organophosphorus carbamate and cholinesterase have a special biochemical reaction: after the hydrolysis of cholinesterase, products of the hydrolysis react with a certain chromogenic reagent, the color changes after the reaction. But the reaction is affected by the pesticide of organophosphorus carbamate, they can restrain the reaction and the color will not change. The inhibitory rate is correlated with the concentration of pesticide positively. The system can judge the degree of the pesticide of organophosphorus carbamate in the samples by detecting the inhibitory rate.
The working process is: the monochromatic light generating from the LED goes through the solution which is put into an 8*12 holes test-tube moved by a step-motor and shoots to silicon photocells. The photocells convert the light signal to current signal. The current signal is transported to a amplifier circuit and is changed into voltage signal which is subsequently received by A/D converter of a MCU. The MCU is in charge of controlling the step-motor, display, communication and data processing.
The system uses C8051020F device as its MCU. The C8051F020 family utilizes Silicon Labs' proprietary CIP-51 microcontroller core. The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute with a maximum system clock of 12-to-24 MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with only four instructions taking more than four system clock cycles.
The most unique enhancement is the Digital Crossbar. The on-chip counter/timers, serial buses, HW interrupts, ADC Start of Conversion input, comparator outputs, and other digital signals in the controller can be configured to appear on the Port I/O pins specified in the Crossbar control registers.
The C8051F020 has an on-chip 12-bit SAR ADC (ADCO) with a 9-channel input multiplexer and programmable gain amplifier. With a maximum throughput of 100ksps, the ADC offers true 12-bit accuracy. The internal voltage reference circuit consists of a 1.2 V, 15 ppm/℃(typical) bandgap voltage reference generator and a gain-of-two output buffer amplifier. So using the internal voltage requires that the input current must be lower than 2.4V.
Eight light-emitting diodes are used as light source of which light shoots to the solutions. A voltage stabilizer LM317 supplies a stable voltage to the diodes. During the course of measuring, diodes should be lighted one by one so as not to cause interference to adjacent ones. As a result a decoder 74LS138 is used. Since the output current of 74LS138 is not enough to light the diodes, two power transistors 9013 are connected to a diode.
The acquisition circuit is composed of eight silicon photocells and an analog multiplexer CD4051. The current signal emitted by the photocell is so weak that the MCU can not detect exactly. So the output of CD4051 is connected to the input of an amplifier circuit. The amplifier circuit contains a low-pass filter and an integrated operational amplifier OP07. The out voltage from the amplifier circuit and the signal ground are connected to the differential input ports of a instrumentation amplifier AD623 which is configured for unity gain (G = 1) in order to eliminate the common-mode interference.
The system equips a four-phase inductor 47BYGH107 type step-motor. Its driving circuit has four triodes TIP122 and four diodes IN4003. It makes multi-detecting possible and the number in one time detecting can be 96.
The system employs a LCM240128 made by XINHUALONG Corp. to display the result. The module contains LCD display, driving circuit, controlling module T6963C made by TOSHIBA,PCB main board ,RAM, and backup light.
A 4*5 matrix keyboard is used and its nine controlling lines are all linked to the I/O ports of the MCU.
The system has the capability of storing 1000 results by using a EEPROM AT24C512 even when it is not powered. The SMBus0 I/O interface between AT24C512 and MCU is a two-wire, bi-directional serial bus. It is compatible withthe I~2C serial bus.
It is convenient for users to confirm and record the time by using a real time clock chip SD2303. In this system users could get or modify the time at any time. The interface between SD2303 to MCU is also a two-wire serial bus.
A serial printer made by WEIDA is used. It makes that the result can not only be stored in the EEPROM, but also be printed out for people to check out.
The system employs a portable switch power. Other internal voltages can be got by using some DC-DC converters.
The system is programmed with C language under the development environment of Keil C uVision 2. Modularized programs consist of: multi-chinese character menu, displaying and modifying time, measuring and storing the result, querying and printing the history data and connecting to PC.
To validate the dependability and stability of the whole system, a common kind of fast measuring reagent for pesticide residues is used to detect the samples. The result is satisfied, the whole system is succeeded.
The whole system performed well in the experiment. We should developed it and make more advantage. An improved system can distinguish the kind of a pesticide and also quantitative analysis can be realized.
引文
[1]赖麒文.8051单片机C语言彻底应用.科学出版社.2002年1月第1版
[2]张海峰等.基于AT89C2051的滤光片自动切换系统.《光电子技术》.2005.9
[3]洪家平SD2003型实时时钟及其I~2C接口设计.《国外电子元器件》2005年第11期
[4]张媛媛等.基于C8051F020的温湿度控制箱设计.《国外电子元器件》2004年第10期
[5]杨子夫等.舞蹈机器人步进电机驱动电路和程序设计.《计算机应用》.2002
[6]刘树吉.针式打印机工作原理.国防工业出版社.1988年12月第1版
[7]何立民.MCS-51系列单片机应用系统设计.北京航空航天大学出版社.2000
[8]谢承恩等.食品安全检测中的分析测试技术进展分析.维普资讯.2005.4
[9]张迎新等.C8051F系列SOC单片机原理及应用.国防工业出版社.2005.8
[10]楼然苗等.51系列单片机设计实例.北京航空航天大学.2003.8.
[11]李劲松,武培秀.点阵LCD器汉字程序设计.电测与仪表.2003.
[12]李维諟,郭强.LCD应用技术.北京工业出版社.2000.
[13]张毅刚,彭喜源等.单片机应用设计.哈尔滨工业大学出版社,1997.
[14]黄圣国等.智能仪器.北京 航空工业出版社.1993
[15]王宜怀.单片机原理及其嵌入式应用教程.希望电子出版社.2002
[16]Jan A xelson 著,那怡超等译.并行端口大全.中国电力出版社.1998
[17]朱庆保.微机测控系统实用抗干扰研究.测控技术.1996,15
[18]刘迎春.传感器原理设计与应用.国防科技大学出版社.2002.2
[19]石志熹等.PC机用于实施监测系统的几项技术.电子测量与仪器学报.1994,8
[20]李华等.MCS-51系列单片机实用接口技术.北京航空航天大学出版社.1993.1
[21]钮金真,胡庆云,杨明权.用Visual C++6.0开发Windows98环境下串行通讯程序.中央民族大学学报.2001.10
[22]顾天柱/陈巳康C51交叉编译系统.上海复旦大学出版社.1990.8
[23]康华光.电子技术基础 模拟部分(第四版).高等教育出版社.1998.
[24]阎石.电子技术基础 数字部分(第四版).高等教育出版社.1997.
[25]]罗庆尧,邓延伸,蔡汝秀,曾云鹗.分光光度分析.科学出版社.1998.
[26]LCM SPECIFICATIONS.北京青云创新科技发展有限公司
[27]潘琢金.C8051F020混合信号ISPFLASH微控制器数据手册.2005.2
[28]姜远海等 医用传感器 科学出版社.1997.6
[29]Texas Instruments.Data sheet of CD4051.1998.8
[30] Intesil.Dual RS-232 Transmitter/Receiver ICL232.1997.8
[31] On Semiconductor. 1.5 A Adjustable Output. Positive Voltage Regulator LM317.2004
[32] TOSHIBA CMOS Digital Intergrated Circuit Silicon Monolithic T6963C.1998.10
[33] NPN Darlington-Cconnected Silicon Power Transistors TIP122.1990
[34] NPN Silicon Transistor TIP9013.1990
[35] DC-DC Converter Control Circuits.MC34063.2001.3
[36] 3-Line TO 8-Line Decodes/Demul Tiplexers.Texasinstruments. SN74LS138.1972
[37] Rev1.4 Silicon Labs.C8051F020.2000.5
[38] 8-Bit Parallel In/Serial Output Shift Registers. DM74LS165.1986.8
[39] Datasheet of Hex Inverters.SN7404.Texas Instruments. 1988
[40] Fairchild Semiconductor Corporation.1N4001-1N4007.2001
[41] CMOS Programmable Peripheral Interface.Intersil CORP.82C55A. 1998.7
[42] Analog Devices.AD623.
[43] Analog Devices.OP07
[44] 2-Wire Serial EEPROM 512K.AT24C512.Atmel CORP.2005
[45] Specifications and Pin No. VS Phase of 17PU-H. Minebea-Matsushita Motor Corporation.2000
[46]High Voltage/High Cerrent Darlington Transisitor Arrays. ULN2003. Signetics Products. 1986.11
[47] Lipovski G. Jack.Microcomputer interfacing: Principles and practices .G. Jack Lipovski. Lexington Books, 1980
[48] Jun Shen, Serge Castan. An Optimal Linear Operator for Step Edge Detection. Graphical Models and Image Processing.Vol.54.No.2.1992
[49] Fairchild Semiconductor Corporation.MC78XX.2001
[50] Sergio Franco.Design with Operational Amplifiers and Anolog Integrated Circuiits.2004
[51] M.E.Van Valkenburg.Analog Filter Design.Holt, Rinehart and Winston, Orlando, FL, 1982
[2]张海峰等.基于AT89C2051的滤光片自动切换系统.《光电子技术》.2005.9
[3]洪家平SD2003型实时时钟及其I~2C接口设计.《国外电子元器件》2005年第11期
[4]张媛媛等.基于C8051F020的温湿度控制箱设计.《国外电子元器件》2004年第10期
[5]杨子夫等.舞蹈机器人步进电机驱动电路和程序设计.《计算机应用》.2002
[6]刘树吉.针式打印机工作原理.国防工业出版社.1988年12月第1版
[7]何立民.MCS-51系列单片机应用系统设计.北京航空航天大学出版社.2000
[8]谢承恩等.食品安全检测中的分析测试技术进展分析.维普资讯.2005.4
[9]张迎新等.C8051F系列SOC单片机原理及应用.国防工业出版社.2005.8
[10]楼然苗等.51系列单片机设计实例.北京航空航天大学.2003.8.
[11]李劲松,武培秀.点阵LCD器汉字程序设计.电测与仪表.2003.
[12]李维諟,郭强.LCD应用技术.北京工业出版社.2000.
[13]张毅刚,彭喜源等.单片机应用设计.哈尔滨工业大学出版社,1997.
[14]黄圣国等.智能仪器.北京 航空工业出版社.1993
[15]王宜怀.单片机原理及其嵌入式应用教程.希望电子出版社.2002
[16]Jan A xelson 著,那怡超等译.并行端口大全.中国电力出版社.1998
[17]朱庆保.微机测控系统实用抗干扰研究.测控技术.1996,15
[18]刘迎春.传感器原理设计与应用.国防科技大学出版社.2002.2
[19]石志熹等.PC机用于实施监测系统的几项技术.电子测量与仪器学报.1994,8
[20]李华等.MCS-51系列单片机实用接口技术.北京航空航天大学出版社.1993.1
[21]钮金真,胡庆云,杨明权.用Visual C++6.0开发Windows98环境下串行通讯程序.中央民族大学学报.2001.10
[22]顾天柱/陈巳康C51交叉编译系统.上海复旦大学出版社.1990.8
[23]康华光.电子技术基础 模拟部分(第四版).高等教育出版社.1998.
[24]阎石.电子技术基础 数字部分(第四版).高等教育出版社.1997.
[25]]罗庆尧,邓延伸,蔡汝秀,曾云鹗.分光光度分析.科学出版社.1998.
[26]LCM SPECIFICATIONS.北京青云创新科技发展有限公司
[27]潘琢金.C8051F020混合信号ISPFLASH微控制器数据手册.2005.2
[28]姜远海等 医用传感器 科学出版社.1997.6
[29]Texas Instruments.Data sheet of CD4051.1998.8
[30] Intesil.Dual RS-232 Transmitter/Receiver ICL232.1997.8
[31] On Semiconductor. 1.5 A Adjustable Output. Positive Voltage Regulator LM317.2004
[32] TOSHIBA CMOS Digital Intergrated Circuit Silicon Monolithic T6963C.1998.10
[33] NPN Darlington-Cconnected Silicon Power Transistors TIP122.1990
[34] NPN Silicon Transistor TIP9013.1990
[35] DC-DC Converter Control Circuits.MC34063.2001.3
[36] 3-Line TO 8-Line Decodes/Demul Tiplexers.Texasinstruments. SN74LS138.1972
[37] Rev1.4 Silicon Labs.C8051F020.2000.5
[38] 8-Bit Parallel In/Serial Output Shift Registers. DM74LS165.1986.8
[39] Datasheet of Hex Inverters.SN7404.Texas Instruments. 1988
[40] Fairchild Semiconductor Corporation.1N4001-1N4007.2001
[41] CMOS Programmable Peripheral Interface.Intersil CORP.82C55A. 1998.7
[42] Analog Devices.AD623.
[43] Analog Devices.OP07
[44] 2-Wire Serial EEPROM 512K.AT24C512.Atmel CORP.2005
[45] Specifications and Pin No. VS Phase of 17PU-H. Minebea-Matsushita Motor Corporation.2000
[46]High Voltage/High Cerrent Darlington Transisitor Arrays. ULN2003. Signetics Products. 1986.11
[47] Lipovski G. Jack.Microcomputer interfacing: Principles and practices .G. Jack Lipovski. Lexington Books, 1980
[48] Jun Shen, Serge Castan. An Optimal Linear Operator for Step Edge Detection. Graphical Models and Image Processing.Vol.54.No.2.1992
[49] Fairchild Semiconductor Corporation.MC78XX.2001
[50] Sergio Franco.Design with Operational Amplifiers and Anolog Integrated Circuiits.2004
[51] M.E.Van Valkenburg.Analog Filter Design.Holt, Rinehart and Winston, Orlando, FL, 1982