【正文】
system adopts infrared measuring temperature sensor of TN series to measure the target temperature and displays the data on the LCD screen with the STM32. At the same time, it bines with the LabVIEW programming to achieve the purpose of the remote control. Different from the noncontact temperature measurement technology, this system holds more advantages, which response fast, measure widely and so on. Meanwhile, convenience is also been provided for the daily life and industrial production. Introduction It’s a traditional way to measure temperature with the contact method. However, it can only measure an object which reaches thermal equilibrium state with temperature sensor. The direct result is a long response time, easily affected by environmental temperature and declined accuracy of measurement. Compared with the traditional measuring way, infrared temperature measurement technology own more advantages at the accuracy of measurement. Meanwhile, it is convenient of detecting the temperature with a fast speed. Because of that, the infrared temperature measurement technology bees one of the most important detecting methods. This paper will introduce a device using the infrared temperature measurement technology. The device uses TN901 as the sensor to measure the temperature. It uses STM32 as the master and uses TN901 and DS1624 as the slaves. At the same time, the STM32 can transfer the actual temperature to the principle puter through the work. The principle puter uses LabVIEW as the software to control the munication with the STM32. This device can measure the temperature any time any where. It brings great convenience for longdistance observation target temperature and operating the machine system. The Principle Infrared radiation is one of the most widely existing in the nature of the electromagic wave radiation, which is based on any object in a conventional environment will produce their own molecular and atomic motion without rules. Meanwhile, the object will radiate energy ceaselessly. Molecules and atoms move more intense, the greater the radiation energy. On the contrary, the radiation energy will be less. Therefore, we can measure the infrared energy so as to detect the temperature of the object. That’s the objective basis of infrared 陜西理工學院畢業(yè)設計 第 23 頁 共 67 頁 radiation temperature measurement. According to the Stephen Boltzmann law, the higher the temperature of the object, the more energy will be out of its radiation. When the temperature is T, the intensity of the object radiated in all wavelengths is: M b =εσT 4 (1) In the Equation, the σ is the Stephen Boltzmann constant。 the T is the absolute temperature of the objects。 the ε is the normal emissivity of the objects surface, if the object is an absolute black, the ε is one, or else it is less than one but larger than zero. The infrared measuring sensor receives the energy which is radiated by the target, then the sensor transfer the energy into electrical signal. The signal will be magnified by the amplifier and changed to the temperature of the object to be measured. TN901, the infrared sensor, is a good example. Its principle diagram is shown in Fig. 1. The infrared pyroelectric sensor is located at the focus of a concave mirror which is after a filter. So the sensor can receive the infrared energy with concentration. After this, an amplifier is designed to magnify the signal. Then an analogydigital converter converts the analog signal to digital signal. Finally, according to the related formula of Stephen Boltzmann law and Wayne displacement law, we can calculate the surface temperature of the object to be tested. Design Scheme The infrared temperature measurement system is posed of several big modules, respectively is the STM32 master control module, the infrared temperature measurement module, the display module, the PC remote control module and the power module. The system overall frame is shown in Fig. 2. The STM32 control the TN901 to temperature acquisition, then the TN901 exchange data with STM32. The STM32 will display the real time temperature on the LCD screen. As long as under the condition of work allows, the STM32 can realize the munication with the LabVIEW at any time. The STM32 use the protocol of TCP/IP to transfer data to PC, the PC use the software LabVIEW to control the temperature acquisition start or stop in a remote mode. This function will give the user convenience at any time checking the situation of the target temperature and operating the measuring system. In order to present the advantages of fast response, measurement precision of the infrared 陜西理工學院畢業(yè)設計 第 24 頁 共 67 頁 technology, we use the contacted measuring unit DS1624 to collected temperature. By contrast, the infrared measuring technology will be very good highlight the advantages. Program Design This system mainly includes two parts of program design, respectively is the process of the lower machine and the PC program design. The lower machine program design mainly includes the capturing temperature and displaying. The PC program design mainly includes the remote monitoring of the target temperature captured by the lower machine and the state of the lower machine. Hardware Design Program 陜西理工學院畢業(yè)設計 第 25 頁 共 67 頁 According to the requirements of structured programming, we use modularization and structured programming mode to design the program. Based on the function of the system, the program module contains the following: the main program module, power control module, temperature measurement module, LCD module, interrupt module, the DMA function module and so on. The detailed program schedule is shown in Fig. 3. The main Program Module The