【正文】 高級編程語言相比，可更加有效的利用系統(tǒng)資源，提高系統(tǒng)運行的實時性。，便于程序設計和調(diào)試。，加入軟件抗干擾措施，與硬件抗干擾措施相結(jié)合，有效提高系統(tǒng)抗干擾能力。千萬不要刪除行尾的分節(jié)符，此行不會被打印。“結(jié)論”以前的所有正文內(nèi)容都要編寫在此行之前。 50 結(jié)論智能變送器，是計算機技術、檢測技術與通信技術匯合的結(jié)果。本論文在參考國外現(xiàn)場總線產(chǎn)品及有關智能變送器的技術資料的同時，根據(jù)國情和自身現(xiàn)有實驗條件，按照經(jīng)濟、實用、可靠的設計要求，對選用輸出不同幅值的弱信號多傳感器應用系統(tǒng)，設計一種具有6個檢測通道的通用主機，利用儀表運算放大器AD623和數(shù)控電位器X9241設計了增益自調(diào)節(jié)信號高精度放大電路，采用12位串行接口、具有自診斷功能A/D轉(zhuǎn)換器TLC2543完成模擬信號到數(shù)字信號轉(zhuǎn)換，經(jīng)80C52單片機采集處理后，由D/A將經(jīng)過處理的數(shù)字信號轉(zhuǎn)換成模擬信號，再由V/I轉(zhuǎn)換電路變換為4~20mA DC標準信號，以保持與模擬儀表兼容，同時經(jīng)光電隔離和RS485接口，實現(xiàn)遠程數(shù)字信號傳輸，達到了設計的目的。本設計仍有許多需要改進和完善的地方，主要有以下幾個方面：，如應用現(xiàn)場的溫度、濕度變化，對傳感器帶來的影響和由此需進行的補償工作。，使之成為可組態(tài)儀表。由于時間關系和本人能力所限，盡管盡了很大的努力，但設計中難免存在一些錯誤和不足之處，敬請各位老師批評指正。致謝本文是在導師xx老師的悉心指導下完成的。我在本科畢業(yè)設計期間以及平時的課業(yè)知識方面均得到了xx老師的指導。導師嚴謹?shù)闹螌W態(tài)度、淵博的知識、豐富的工程實踐經(jīng)驗和一絲不茍的工作作風給我留下了深刻的印象，xx老師對我的教誨使我受用終生。值此論文完成之際，謹向xx老師表示深深的謝意。在論文的寫作和課題的設計和開發(fā)中，以及在xx大學學習期間，我得到了自動化學院老師的支持，感謝他們在百忙之中對我的幫助和關懷，在此一同表示感謝。最后，對在我學習生活中給予我?guī)椭耐瑢W表示衷心的感謝！參考文獻1楊慶柏，1998，(9)：42—442 李全利，仲偉峰，2006，2000，(1)：13—154 ：35375 ，19996 ，19927 姜偉光，國外電子元器件，2002，(5)：48—518 楊慶柏，1998，(9)：42—449 張大波，趙海，199510 ，11 ，12 ，13 ，14 (信息科學版)，15 and sensor excitation and measurement techniques Electronic engineering,2000,(10),25—3816 device —acquisition book,1984:20—56附錄ATransducer and sensor excitation and measurement techniquesMany of today39。s industrial and instrumentation applications involving sensor. The function of the sensor system is to monitor changes, and then this data back to the main controller. For a simple voltage or current measurement sensors may be resistance in nature. However, some sensor system may be inductive or capacitive in nature, that is to say, the frequency range of the sensor resistance change is nonlinear. Impedance sensors such typical example is the proximity sensor a campaign for the detection of the relative distance of objects。 In addition, capacitive sensors or sensor sensibility in the medical devices used to measure blood flow or blood pressure or blood qualitative analysis. In order to use these plex impedance sensors, the realization of measurement, to provide an exchange of (AC) excitation source frequency in the frequency range of the sensor for scanning. This article attempts to explain how the use of singlechip digital waveform generator to easily achieve this up to 10 MHz frequency scanning. Also introduced a kind of integrated incentive, response and digital signal processor (DSP) features a plete singlechip sensor solution that suited the requirements of up to nearly 50 kHz frequency applications. Sensors: working principle.Inspired by the frequency of sensor signals based on sensor values of L or C to show the corresponding instantaneous magnitude, frequency or phase changes. For example, the ultrasound will show a flow of phase offset, while the proximity sensor will cause the rate to change. Tracking changes in impedance that is the most monly used to monitor the resonant frequency circuit. Capacitance value of the resonant frequency is equal to the frequency where the inductance value point. This is also the largest frequency curve frequency impedance value of the corresponding point. Under normal circumstances, for example, in static conditions, the sensor L, R and C has a unique value, in the resonant frequency impedance to Department with the greatest value. When a moving object near the sensor, then sensor L and C values will be changed and a new resonant frequency. By monitoring the changes in resonant frequency (and thus lead to changes in impedance), it is possible to speculate that the relative movement of objects moving away from the sensor.Calculated resonant frequency: calculation circuit measuring the resonant frequency of the need for the relationship between frequency and impedance, in particular, need a certain frequency range with the ability to scan the waveform generator. A simple, lowcost method is based on the AD5930 waveform generator. AD5930 with a group of preset in the frequency range of the ability to provide a linear scan. Once the conditions for setting, on the need for further control, in addition to a frequency scan for the start of the trigger. AD5930 has many advantages: the output frequency resolution of 28 bit, so you can be less than the control accuracy of Hz output frequency. The output frequency range of 0 ~ 10 MHz, thus the selection of sensors with a lot of flexibility. For example, some sensors a very narrow frequency range, but the requirements in this frequency range with high resolution. Some sensors may require a wide frequency range, but lower resolution requirements. This approach is easy to calculate the resonant frequency of the sensor. System block diagram: typical block diagram of such a system as shown in Figure 3. Through the BF535 DSP processor AD5930 digital waveform generator set. AD5930 needs arising from the sinusoidal output voltage waveform for lowpass filtering and amplification in order to eliminate the master clock (MCLK), mirroring the frequency and high frequency noise generated by feed through. After filtering the sensor signal can be used as a source of excitation frequency. According to the impedance of the sensor response signal amplification may be needed in order to enter the ADC (ADC) dynamic range. Sensor output and the frequency of the source of both incentives into the AD7266 12 bit, 2 MSPS dual simultaneous sampling ADC. ADC output data will be stored in memory in order to do further analysis to calculate the phase and amplitude of the sensor offset. Complete integrated sensor solutions: separation described above is a mon solution for impedance measurement of the sensor solution. The program may require many discrete ponents, so the sensor is a costanalysis solution. These separate ponents will increase their own sources of error. The design of active ponents will increase the number of phase error, which is the need for correction.