【正文】 ；（4）CLRCLR2為直接復(fù)位端（低電平有效）；（5）PRPR2為直接置位端（低電平有效）。2mV；（6）共模輸入電壓范圍寬，VIC=0～；（7）輸出與TTL，DTL，MOS，CMOS 等兼容；（8）輸出可以用開路集電極連接“或”門；（9）表面安裝器件:表面安裝。由圖可知皮帶走速的測量步驟如下：（1）由測速傳感器輸出的信號(hào)，其頻率為皮帶走速的線性函數(shù)，該頻率由光碼盤檢測回路獲得；（2）該輸出信號(hào)通過衰減送給比較器整形為標(biāo)準(zhǔn)脈沖信號(hào)，輸入到74LS74進(jìn)行分頻，74LS74的Q輸出方波接到8051的；（3）由8051的定時(shí)器測出方波的周期，然后選用門控方式定時(shí)計(jì)數(shù)，當(dāng)Q輸出高電平時(shí)T1計(jì)數(shù)，當(dāng)Q輸出低電平時(shí)T1停止計(jì)數(shù)，最后讀出的計(jì)數(shù)值m；圖35：皮帶走速信號(hào)測量電路（4）由公式計(jì)算電機(jī)的轉(zhuǎn)速，然后查表得到轉(zhuǎn)換系數(shù)，計(jì)算出皮帶走速大小。其中，第一行的行值是00H，第二行的行值是08H。通常，公共陽極接高電平（一般接電源），其它管腳接段驅(qū)動(dòng)電路輸出端。表31：八段LED顯示器段碼表顯示符0123456789.段碼3FH06H5BH4FH66H6DH07H7DH7EH6FH80H本次設(shè)計(jì)中的顯示器采用八段數(shù)碼管，需要由驅(qū)動(dòng)電路（反向器）來進(jìn)行驅(qū)動(dòng)，并采用共陽極接法。這種顯示為動(dòng)態(tài)顯示，此時(shí)，段選碼和位選碼都是由軟件控制。這種方法的優(yōu)點(diǎn)是線路簡單，價(jià)格便宜。每輸出一個(gè)字節(jié)，8051內(nèi)部的硬件自動(dòng)使SCON寄存器的中斷標(biāo)志TI置位，通過對(duì)TI的測試，即可確定一個(gè)字節(jié)是否發(fā)送完畢。在硬件電路中，74LS164的功能是進(jìn)行鍵掃描時(shí)提供列值以及進(jìn)行LED顯示時(shí)提供段碼。一般用雙極型（TTL）工藝制作的稱為555，用互補(bǔ)金屬氧化物（CMOS）工藝制作的稱為7555，除單定時(shí)器外，還有對(duì)應(yīng)的雙定時(shí)器556/7556。在電源與地之間加上電壓，當(dāng) 5 腳懸空時(shí)，則電壓比較器 C1 的同相輸入端的電壓為2VCC /3，C2的反相輸入端的電壓為VCC /3。物料在超出設(shè)定值或低于設(shè)定值時(shí)就被系統(tǒng)識(shí)別為超限。圖37：報(bào)警電路原理圖由于P1口是準(zhǔn)雙向口，要想將某一位作輸出位時(shí)，必須先在鎖存器中寫入“1”。：（1）分辨率8位；（2）電流穩(wěn)定時(shí)間1us；（3）可單緩沖、雙緩沖或直接數(shù)字輸入；（4）只需在滿量程下調(diào)整其線性度；（5）單一電源供電（+5V～+15V）；（6）低功耗，20mW。本系統(tǒng)DAC0832工作于單緩沖方式，只用輸入寄存器鎖存數(shù)據(jù)。單相橋式PWM逆變電路如圖39所示。當(dāng)勵(lì)磁線圈通過電流時(shí)產(chǎn)生磁場，爪形結(jié)構(gòu)便形成很多對(duì)磁極。在整流、濾波電路之后，還須接穩(wěn)壓電路，保證輸出的直流電壓穩(wěn)定。這種整流電路使用普通的變壓器，但是比全波整流多用了兩個(gè)整流二極管。其作用是當(dāng)交流電網(wǎng)電壓波動(dòng)或負(fù)載變化時(shí)，保證輸出直流電壓的穩(wěn)定。圖312：系統(tǒng)閉環(huán)控制回路原理圖當(dāng)輸送皮帶以運(yùn)作時(shí)，物料在皮帶上一般為不均勻分布，瞬時(shí)流量為： （34）式中：P(t)為單位長度上物料的瞬時(shí)重量； V(t)為皮帶的瞬時(shí)線速度。 輸出控制變量Vi的表達(dá)式為： （38）式中：為上一時(shí)刻輸出的控制變量。系統(tǒng)初始化的主要任務(wù)是在程序開始運(yùn)行時(shí)，對(duì)控制系統(tǒng)中所用到的各個(gè)串行口、地址和定時(shí)器的工作方式進(jìn)行初始化設(shè)定，同時(shí)對(duì)用戶地址進(jìn)行計(jì)算規(guī)劃。，則由逐列掃描找出這個(gè)鍵的所在位置。，說明按下的是功能鍵，則通過散轉(zhuǎn)程序轉(zhuǎn)到各自的入口地址，分別實(shí)現(xiàn)各自的功能。WR鍵的功能為輸入流量設(shè)定值或PID調(diào)節(jié)及線性公式中的系數(shù)(P、I、D、a、b、c、d)。按下此鍵流量設(shè)定值先顯示出來，如需要改變?cè)O(shè)定值，則用鍵盤敲入相應(yīng)的數(shù)字鍵，隨后按下WR鍵即可。按下此鍵，先啟動(dòng)輸送皮帶空轉(zhuǎn)運(yùn)動(dòng)，然后啟動(dòng)A/D轉(zhuǎn)換器對(duì)荷重傳感器的輸出信號(hào)進(jìn)行轉(zhuǎn)換，取若干次結(jié)果的平均值作為皮帶的自重，寫入相應(yīng)單元保存。在本系統(tǒng)中，首先要判別是否已輸入過設(shè)定值，若沒有輸入過，則應(yīng)跳回鍵掃描。根據(jù)定時(shí)器中的值可計(jì)算INT1引腳上出現(xiàn)的正脈沖寬度。故TMOD＝10010000B，即在初始化時(shí)TMOD將置為90H。 顯示程序顯示程序用于顯示計(jì)算出來的瞬時(shí)流量F(t)，它主要是用一個(gè)取整子程序，使瞬時(shí)流量F(t)轉(zhuǎn)換成二進(jìn)制數(shù)，并取出16位的整數(shù)絕對(duì)值和16位的小數(shù)部分，調(diào)用雙字節(jié)二進(jìn)制整數(shù)轉(zhuǎn)換成十進(jìn)制整數(shù)的子程序和雙字節(jié)二進(jìn)制小數(shù)轉(zhuǎn)換為十進(jìn)制小數(shù)的子程序，分別將數(shù)據(jù)轉(zhuǎn)化為十進(jìn)制，并將整數(shù)部分送給45H、44H單元，小數(shù)部分送入42H、41H、40H單元，43H單元送入0AH，即段碼80H，用于顯示小數(shù)點(diǎn)“．”。該系統(tǒng)的設(shè)計(jì)可以比較完善的自動(dòng)處理工作中出現(xiàn)的異常狀況，實(shí)現(xiàn)了漏料、缺料、原料不足等異常情況的自動(dòng)報(bào)警，此系統(tǒng)操作非常簡單，使用性能好，抗干擾能力強(qiáng)，而且不容易出現(xiàn)故障，非常適合工作人員的操作，現(xiàn)今在中國中、小型企業(yè)應(yīng)用最為廣泛。參考文獻(xiàn)[1] [M].北京：中國電力出版社，[2] 李國興,[M].杭州：浙江大學(xué)出版社，[3] 張齊,[M].北京：電子工業(yè)出版社，[4] 楊打生,[M].北京：北京理工大學(xué)出版社，[5] 肖軍,[M].北京：機(jī)械工業(yè)出版社，[6] [M].西安：西安電子科技大學(xué)出版社，[7] 殷剛，[M].北京：北京理工大學(xué)出版社，[8] [M].西安:西安電子出版社，1999[9] [M].北京:高等教育出版社，2004[10] [M].北京:高等教育出版社，2008[11] （第二版）[M].北京:清華大學(xué)出版社，2004[12] Tshilidzi monitoring using putational intelligence methods : applications in mechanical and electrical systems [M].ERT press,2012[13] Soliman Abdelhady Soliman,Ahmad . Electrical load forecasting modeling and model construction [M].Dream Gateway Inc,2010外文原文和譯文Application NoteSensorless Brushless DC MotorControl with Z8 Encore! MCTMMicrocontrollersAbstractThis application note discusses the closed loop control of a 3Phase Brushless Direct Current (BLDC) motor using the Z8 Encore! MC? family of Microcontrollers (MCUs). The Z8 Encore! MC? product family is designed specifically for motor control applications, featuring an onchip integrated array of application specific analog and digital modules. This in turn results in fast and precise fault control, high system efficiency, and onthefly speed/torque and direction control, as well as ease of firmware development for customized applications.This article further discusses ways on how to implement a sensorless feedback control system using a Phase Locked Loop along with Back EMF sensing. Test results are based on using the Zilog BLDC Motor Control Development kit Z8FMC160100KITG. This development kit includes a Motor Control Motor Drive System module with a 32pin Z8FMC16100 MCU, a 3Phase Motor Control Application Board and a 3phase 24 VDC, 30W, 3200RPM BLDC motor with Internal Hall Sensors.Note: This application note was tested with version of ZDS II. Subsequent releases of ZDS II might require you to modify code supplied with this application note.FeaturesThe key features of this reference design include:? Smooth Scurve motor startup with reduced starting current? Sensorless (BackEMF) control using Phase Locked Loop feedback? Microcontrollerbased overcurrent protection? Selectable Speed or Torque Setting? Selectable Speed or Torque Control? Selectable control of motor direction? LED for max speed indication? LED for motoring running indication? LED for Fault indicationDiscussionThe use of BLDC motors has steadily increased over the last several years as the cost of these motors and the technology to control these motors has decreased and the benefits of these motors over other motor types has bee more important than just the initial cost. Variable speed motor applications in industries such as White Goods, Automotive, Aerospace, Medical, and Industrial Automation are now using the BLDC motor over other types of motors, such as Brushed DC and AC Induction.The construction of a BLDC motor gives it several advantages when pared to other electric motors. First, since the BLDC uses electronic mutation it has a longer life when pared with brushed DC motors and requires less maintenance since the brushes on the motor do not require cleaning and replacement. They also run much quieter, both electrically and audibly, because the motor does not have brush arcing and the mechanical mutation of other types of motors. A BLDC motor will generally have a higher output per frame size since the windings are connected to the stator and the heat generated from running can be transferred directly to the motor housing allowing cooler operation. Finally, a BLDC motor will have much lower electrical and friction losses because they don’t need to transfer power from the brushes. These losses are most prevalent at lower loads. The data has shown that a standard BLDC motor will have 510% better efficiency than