【正文】 對于溫度的控制可通過帶光電隔離的過零觸發(fā)型雙向可控硅AC－SSR來實現(xiàn)。 系統(tǒng)中將8155的B口作為顯示接口，經(jīng)74LS48的驅(qū)動器與LED相連，8155的A口的PA3－PA0作為掃描接口，從B口的PB3－PB0讀入列值，鍵盤處理為中斷方式，所以8155的B口工作在兩種方式下：在顯示狀態(tài)時為輸入方式，在鍵盤中斷服務程序處理過程中為輸入方式。 鍵盤顯示系統(tǒng)采用8155芯片控制44矩陣鍵盤和4個七段數(shù)碼管LED顯示，以實現(xiàn)用戶的輸入和數(shù)據(jù)輸出。10V之間，這里以AD574為例。 根據(jù)需要，A/D轉(zhuǎn)換器可采用ADC0809或AD574，ADC0809與AD574不同在于：ADC0809的數(shù)字量是8位，轉(zhuǎn)換時間為100μs，輸入模擬電壓為單極性的0－5V，而AD574的數(shù)字量位數(shù)可設成8位也可以設為12位，且無需外接CLOCK時鐘，轉(zhuǎn)換時間達到25μs，輸出模擬電壓可以是單極性的0－10V或0－20V，也可以是雙極性的177。 由于所測的溫度不同，所以選用的檢測元件也就不盡相同，目前的熱點偶傳感器有：鉑鐒10－鉑熱電偶，其可在1300℃以下范圍長期工作，符號LB；鎳鉻－鎳硅熱電偶，測量范圍在－50～＋1312℃，符號EU等等，溫度傳感器輸出的都是mV信號，而溫度變送器由毫伏變送器和電流/電壓變送器組成，其毫伏變送器就是把溫度傳感器的mV信號變換成mA的電流；電流/電壓變送器再把毫伏變送器輸出的mA電流變成V電壓。 對于溫度控制，可采用適用于工業(yè)控制的單片機組成的自動控制系統(tǒng)， 其系統(tǒng)被測參數(shù)主要是溫度，被測參數(shù)溫度值由熱電偶傳感器測定后得到的mV信號經(jīng)過溫度變送器放大濾波后變?yōu)?－5V的電壓信號，再送到采樣/保持器，經(jīng)過A/D轉(zhuǎn)換器后，將模擬信號變?yōu)閿?shù)字信號進入8031單片機。 在工業(yè)生產(chǎn)中，有很多行業(yè)有大量的加熱設備，如用于熱處理的加熱爐、用于熔化金屬的坩堝爐，以及各種不同用途的加熱爐，反應爐，這樣溫度就成為了工業(yè)對象中一種重要的被測控對象，但是由于爐子的種類，用途不同，因此，采用的加熱方法及燃料也就不同，如煤氣、天然氣、油、電等，但究其控制系統(tǒng)本身的動態(tài)特性而言，基本上都是一階純滯后環(huán)節(jié)。s input and output data. The keyboard of 16 keys for the number keys 09, AF for the function keys, plete set of parameters, the display of choice, automatic / manual conversion, stop and start system. 8155 B of the system will display interface as the mouth, the 74 LS48 drive connected with the LED, 8155 A mouth of the PA3PA0 as scanning interface, from the mouth of the B PB3PB0 read out value, keyboard interrupt way to deal with Therefore, the 8155 B I work in two ways: in the show for the importation of state, the keyboard interrupt service procedures for the importation of processing methods. Singlefrequency alarm can be, in Figure 1, 7406 is the drive, and then in 8031 the mouth, in 8031 to highoutput, low output 7406, the buzzermingthe contrary, Wong buzzer to stop the sound. The temperature control can be isolated with photoelectric trigger a zerotwoway ACSSR SCR to achieve. ACSSR and heating wire series connection in the exchange of power on the 200 V50Hz, ACSSR time can be connected to ACSSR control on a trigger impulse control, with zero detection circuit output by the RP8031 and the output of T0 To trigger ACSSR (hightrigger), if T0 in 1 s, the total for the high, while ACSSR was launched 100 times the maximum power at this time of heating the contrary, if T0 in the total for 1 s LOW, the ACSSR output power of 0, T in a given cycle, as long as the change in ontime ACSSR can change the heater power, to achieve the purpose of regulating temperature. Temperature control procedures to plete the task: 8031,8155 chip initialization and the allocation of memorychip timer and set parameters, temperature sampling, digital filtering, conversion, the judgement of whether the temperature within the specified scope, and overrun the police handling 。 5V or 177。英文文獻the Application of Microputer in Temperature ControlIn industrial production, many industries have a great deal of heating equipment, such as for the heat treatment furnace for melting metal crucible furnace, and the various uses of the furnace, the reactor so that the temperature has bee a target in the industry Control was an important target, but because of the type of stove, use different, therefore, the use of heating fuel and also different methods, such as coal gas, natural gas, oil, electricity, etc., but study of its own control system to the dynamic nature of the case, basically Are part of a band time delay. Practice has proved that for industrial production in the temperature control of the puter control system with high accuracy, strong function, of good economic characteristics, both in improving the quality of products or product volume, energy conservation, or to improve labor conditions, and other show Inparable superiority. The temperature control, can be applied to industrial control of the automatic control system posed of SCM. Its system is the main parameters measured temperature, the temperature parameters measured by the value of thermocouple sensors get the temperature mV signal transmitter to enlarge filtered into a 05 V voltage signal, and then sent to the sampling / holder, after A / D converter, the analog signal into a digital signal into the 8031 microcontroller, a dataprocessing in SCM, on the one hand, and the expectations set by the temperature parison, the bias signal, SCM According to the scheduled PID algorithm to calculate the corresponding control of the control of twoway SCR control of onand off, in order to cut off heating equipment and connectivity and thus control the temperature and stability in the settings, the show sent to the other I, and determine whether there is a need for alarm. As measured by the different temperature, so the optional testing ponents will vary, the current hot dual sensors are: Platinum Lao 10 platinum thermocouple, in 1300 ℃ following longterm scope of work, symbols, LB。提高是有限的，但提高也是全面的，正是這一次設計讓我積累了很多實際經(jīng)驗，使我的頭腦更好的被知識武裝了起來，也必然會讓我在未來的工作學習中表現(xiàn)出更高的應變能力，更強的溝通力和理解力。各種系統(tǒng)的適用條件，各種設備的選用標準，各種管道的安裝方式，我都是隨著設計的不斷深入而不斷熟悉并學會應用的。圖 PWM波形設計結(jié)論畢業(yè)論文是本科學習階段一次非常難得的理論與實際相結(jié)合的機會，通過這次比較完整的溫度控制系統(tǒng)的設計，我擺脫了單純的理論知識學習狀態(tài)，和實際設計的結(jié)合鍛煉了我的綜合運用所學的專業(yè)基礎知識，解決實際工業(yè)過程問題的能力，同時也提高我查閱文獻資料、設計手冊、設計規(guī)范以及電腦制圖等其他專業(yè)能力水平，而且通過對整體的掌控，對局部的取舍，以及對細節(jié)的斟酌處理，都使我的能力得到了鍛煉，經(jīng)驗得到了豐富。仿真圖如下： 熱電偶測溫電路的Proteus仿真電路圖整個系統(tǒng)由鍵盤、顯示、AD采樣、PWM產(chǎn)生四大部分組成。[2] 。按鈕復位電路有兩種可行方案：脈沖復位和電平復位。TTonToff裝入Ton裝入Toff 單片機對PWM控制原理圖 用示波器來表示PWM的輸出電路圖 復位電路的原理 復位是使CPU和系統(tǒng)中的其他部件都處于一個確定的初始狀態(tài)，并從這個狀態(tài)開始工作。將定時器T0 設為16位定時模式,并開啟定時器的中斷允許，則輸出為高電平時，定時器裝入初值： FFFFTon；輸出為低電平時，定時器裝入初值： FFFF(1000Ton)。數(shù)字PID的輸出U（K）限幅值為1000，當U（K）大于1000，則設為1000當U（K）小于0，則設為0。 單片機對PWM控制的實現(xiàn)上節(jié)已述要對PWM進行控制就要控制其功率開關部件的占空比。在一個開關周期內(nèi)，當0≤t＜時，為正，IGBT導通，電源電壓加到熱電阻兩端；≤t＜T時，為零，IGBT關斷，熱電阻失去電源。改變脈沖的占空比就是對脈沖寬度進行調(diào)制，只是因為輸入電壓和所需要的輸出電壓都是直流電壓，依次脈沖既是等幅的，也是等寬的，僅僅是對脈沖的占空比進行控制，這是PWM控制中的最為簡單的一種情況。本設計采用LED的共陰極接法， 共陰七段LED段選碼表[13]：顯示字符數(shù)顯代碼顯示字符數(shù)顯代碼03FH56DH106H67DH258H7F8H34FH880H466H990H LED段選碼表 LED顯示接線圖