基于单片机的电阻测量的外文翻译2.doc

Line resistance measurement instrument making and design The subject line measurement technique is a novel application of electronic measuring technology, also known as equipotential isolation technology. It can accurately measure the electronic devices printed circuit current, resistors, transistors and other parameters without destroying the integrity of the circuit. The basic principle of line resistance measurement circuit is resistance by an integrated amplifier and resistors and other simple vitality composition / number of devices using less voltage converter and easy integration. It does not use the conventional analog resistive measuring instrument and the use of single-chip control of the automatic conversion range of data acquisition and display of data processing to achieve intelligent measurement process. This intelligent online resistance measuring instrument has a simple circuit, high accuracy, easy operation, intuitive display characteristics of the circuit is modified to complete the line capacitance and line inductance measurements can be converted into capacitors, inductors, resistors with three-line measurement instrument. The design of future electronic applications in the field of design has a very wide range of applications for our future measurements played a good help.To make online resistance meter to be more precise the measured resistance is displayed on the digital design into five major parts to be completed are the Rx / V conversion circuit scale conversion and display range A / D converter chip control part of the LED display section.The key line resistance measuring instrument lies in the Rx / V converter that line resistance Rx Rx / V converter is designed to achieve electrical isolation function, resistance is converted into a voltage and other functions. This part of the circuit is used in computing the ratio of the inverting input of the op amp circuit with integrated virtual short, false break principle clever achieve electrical isolation effect. MCU control part of this program will be a vital part of this involves a range of automatic conversion application MCU can automatically switch range to achieve ease of operation according to the measured resistance. In the automatic conversion of our range is applied to the CD4051. The second is the A / D converter which can convert continuous analog signal into a binary number where I used the ADC0809. Finally, the display portion of the circuit is a circuit uses a LED display digital values were positive for the A / D conversion for display. Detailed design and analysis of each module in the circuit several sections of this chapter in accordance with the following hardware schematics. Measured resistance Rx after Rx / V converter converts this voltage into a voltage U through dual limit comparator 0-5V A / D LED display section, Rx / V converter to draw a double limit comparator high and low to the microcontroller , P2.1, P2.1 is high so that the microcontroller to control the range conversion. As to the appropriate range when P2.1 is low at this time that the measured resistance Rx turned into a voltage U microcontroller A / D converter to IN-0 U port analog signals into digital signals transmitted through the data port to P0 SCM. Digital voltage signal through software programming data is then converted into resistance by P1 and P3 data port control port for LED dynamic display.The design requirements by single-chip display circuit resistance is measured by a conversion circuit must be converted to a voltage signal to the resistance in order to transmit the data to the data acquisition system. Data conversion circuit into three parts Rx / V converter circuit scale display range conversion circuit. Rx / V converter circuit line key technical resistance measuring instrument is Rx / V conversion circuit that online Rx resistance. No matter how complex the circuit elements can always be put in parallel with the Rx equivalent to each of the two series resistors R and R which constitutes a triangle resistor network. This converter is the role of the RR electrical isolation to eliminate the influence of RR on Rx. Rx input into the analog signal to the analog voltage signal U is input to the A / D converter into a digital signal.Resistance range is what we want to use a reference resistor connected CD4051.The inverting input of the op amp is the ratio of the arithmetic circuit whose voltage shunt feedback is negative feedback due to the high open-loop gain of the differential mode to meet the depth of the negative feedback condition integrated amplifier operating in the linear region and therefore the op amp has a virtual short false break characteristics. Since C grounding point D virtual ground so it was the same potential across R1 R1 therefore UR10 the equivalent circuit.And the characteristics of the load resistor R2 of 0 has no effect on the output voltage according to the depth of the output voltage negative feedback resistor.R1 and R2 so that it can not afford to split the role of the resistance Rx can be measured directly.S test voltage test current. Let the current flowing through the Rx R1 respectively x1. According to Kirchhoffs law, and the current flowing into the inverting input terminal is 0 according to known sx and virtual ground principle 1 0 cd1 R10 may therefore negligible sx 1-2 thus obtained was ground to consider a virtual ground point so sR0 1-3 and then deduce Rx 1-4 obviously just use a digital voltmeter measure the voltage drop across R will be able to find the R-value.If seen from the above circuit resistor Rx right side and not directly to ground, then the output voltage is 0 so that Rx / V conversion is not established.Can be seen by the formula Ux-ERx/Ro if Ux and Ux is proportional Rx Rx Ux impossible but actually it tends to infinity applied voltage op amp to the limit but in reality it can Rx which tends to infinity it means that when the measured resistance Rx to a certain extent does not exist a corresponding value of Ux.译文 在线电阻测量仪的制作与设计本课题应用的在线测量技术是一种新颖的电子测量技术亦称等电位隔离技术。它能在不破坏电路完整性的前提下准确测量电子设备印制线路中的电流、电阻、晶体管等参数。该在线电阻测量电路的基本原理是由集成运放和电阻等简单元气件组成的电阻/电压变换器且采用的器件数目少易于集成化。它不采用以往模拟式的电阻测量仪而采用单片机的控制进行数据采集自动转换量程数据处理和显示等实现测量过程中的智能化。此智能在线电阻测量仪具有电路简单、测量精度高、操作简单方便、显示直观等特点对电路稍加改动即可完成在线电容和在线电感的测量又可改装成电容、电感、电阻三用在线测量仪。该设计在今后的电子应用设计领域中都有非常广泛的应用为我们今后的测量起了很好的帮助。为了让在线电阻测量仪能够更加精密把被测电阻的阻值显示在数码管上把设计分为5个重要部分来完成分别是Rx/V转换电路量程转换和显示量程A/D转换器单片机控制部分LED显示部分。在线电阻测量仪的关键就在于Rx/V转换器Rx即在线电阻Rx/V转换器的设计能实现“电隔离”功能、电阻转换成电压等功能。这部分电路所采用的是反相输入比例运算电路利用集成运放的“虚短”、“虚断”原理巧妙的达到“电隔离”的效果。单片机控制部分将会是这个方案中至关重要的一部分这个牵涉到量程的自动转换问题应用单片机可以根据所测电阻自动切换量程达到操作方便。在量程的自动转换问题上我们应用到的是CD4051。其次就是A/D转换器它可以将连续的模拟信号转换成二进制数在这里我采用的是ADC0809。最后就是电路的显示部分显示电路采用的是LED数码管共阳用来将A/D转换的值进行显示。在本章下面几个小节中将根据这个硬件原理图对各个模块电路进行详细的设计和分析。 被测电阻Rx经过Rx/V转换器转换成电压U此电压经过双限比较器0-5VA/D LED显示部分,Rx/V转换器双限比较器 得出一个高低电平给单片机,P2.1,P2.1为高电平时让单片机来控制量程转换。当转到适当的量程时即P2.1为低电平时此时被测电阻Rx转换成电压U单片机开启A/D转换器把IN-0口模拟信号U转换为数字信号通过P0数据口传输给单片机。数字电压信号经过软件编程