【正文】 set each pitch point temperature value setting for every room, and realize the entire building temperature realtime examination, by the LCD demonstration examination result, the unusual situation is reported by the warning through speech Property by the signal and controlled through the gate of air conditioning’s system , realization energy conservation goal. The system design goal is measure and control temperature in a building each room, because measured the temperate point and control point is dispersion, therefore the system uses the distributional structure, The console is connected each part of control pitch point distributing in the building through the CAN Bus. System structure diagram like figure 1 shows The console hardware design The AT89C52 MCU is the primarily controller in console, It connects with the 共 4 頁(yè) 第 6 頁(yè) warning module, the memory module, the clock/calendar electric circuit and the keyboard module. its structure drawing see Figure 2. The control pitch point also is controlled by the MCU, connected temperature examination module and the CAN Bus interface module. The system has used the AT89S52, it is a section low power chip that is produced by ATMEL Corporation, has 4 KB insystem programmable (ISP) FLASH memory integrated. The scene programming debugging and the system function changing is much conveniently flexible, using AT89S52 to take the system the master controller. When system normal work. The console send a definite control temperature value to a designate pitch point Distributed in the building through the CAN Bus. The pitch point receive the console’s orders and read the temperature detector DS18B20 temperature value distributed in each room through 1Wire bus, transmits each room temperature data and the number of room to the console through the CAN Bus. According to the definite temperature value which receives from console control the air gate of airconditioning system in each room. After receive the data a pitch point send to, the console reads the time from realtime clock/calendar chip PCF8563 through the I2C Bus, with the data which just received store to the memory AT24C128, then process each room temperature value. When the value achieve the data which is established from keyboard in advance, the console output warring to the alarm circuit on reports the alarm. Meanwhile the room number, the time and the temperature value delivers the LED display circuit to display. Every room alarm temperature value is established through the keyboard input module, the console process value and stores in the memory corresponding the input. The CAN Bus interface design The CAN Bus corresponds high as 1 Mb/ s, the most longdistance range may reach 10 km。 2。 4. 結(jié)論 實(shí)地測(cè)試后，該系統(tǒng)可 以有效的 實(shí)現(xiàn) 樓宇 溫度檢測(cè)與控制 .并且 該系統(tǒng)可以應(yīng)用到其他設(shè)備 的 檢測(cè)和控制，以實(shí)現(xiàn) 樓宇 智能化管理。 2． 2 CAN 總線接口設(shè)計(jì) CAN 總線通信的波特率高達(dá) 1Mb／ s，最遠(yuǎn)通信距離可達(dá) lOkm； CAN 總線通信采用短幀結(jié)構(gòu)，使得數(shù)據(jù)傳輸?shù)臅r(shí)間短，受干擾的概率低，并且 CAN 總線協(xié)議有良好的檢錯(cuò)措施，因此 CAN 總線通信的可靠性較高，可以應(yīng)用于有較強(qiáng)干擾的環(huán)境． CAN 總線定義網(wǎng)絡(luò)中的每一節(jié)點(diǎn)對(duì)應(yīng)一地址，在實(shí)際應(yīng)用中， CAN 總線最多可掛 110 個(gè)節(jié)點(diǎn)．基于 CAN 總線通信對(duì)于傳送的信息幀可以設(shè)定不同的優(yōu)先級(jí)，并通過(guò)總線仲裁機(jī)制使高優(yōu)先級(jí)的信息能夠被優(yōu)先、及時(shí)地傳送，保證了更重要的信息能及時(shí)地被傳送，從而增加了 CAN 總線通信的實(shí)時(shí)性． CAN 總線接口采用 PHILIPS 公司生產(chǎn)的 CAN 控制器 SJAl000 和 CAN 驅(qū)動(dòng)器PCA82C250． SJAl000 是集成的獨(dú)立 CAN 控制器 (與 PHILIPS 早期的 CAN 控制器 PCA82C200完全兼容 )，負(fù)責(zé)完成 CAN 總線通信協(xié)議的物理層 和數(shù)據(jù)鏈路層的功能閣． SJAl000 內(nèi)置控制寄存器、命令寄存器、狀態(tài)寄存器、中斷寄存器和收、發(fā)寄存器等，單片機(jī)就是通過(guò)讀寫(xiě)這些寄存器來(lái)實(shí)現(xiàn)對(duì) SJAl000 的控制；芯片的 TXO、 RXO 引腳用于與 CAN 總線收發(fā)驅(qū)動(dòng)芯片相連． PCA82C250 是專(zhuān)門(mén)用于 CAN 總線收發(fā)驅(qū)動(dòng)的 8 腳芯片， TXD、 RXD 引腳分別接收和發(fā)送 CAN 總線控制器的信號(hào)；雙絞線 (同軸電纜 )傳輸介質(zhì)分別接至 CANH、 CANL 引腳．考慮到使用現(xiàn)場(chǎng)可能有各種各樣的干擾，在 CAN 控制器和驅(qū)動(dòng)器之間增加高速光耦隔離器件(6N137) [6]． 2． 3 節(jié)點(diǎn)硬 件設(shè)計(jì) 控制節(jié)點(diǎn)主要包括 CAN 總線接口、控制模塊和溫度傳感器 DSl8820，系統(tǒng)結(jié)構(gòu)如圖 3 所示． Dallas 半導(dǎo)體公司最新單 線 數(shù) 字 溫 度 傳 感 器DSl8820 是一款體積更小、適用電壓更寬、更經(jīng)濟(jì)的數(shù)字化溫度傳感器．現(xiàn)場(chǎng)溫度直接以“一線總線”的數(shù)字方式傳輸，大大提高了系統(tǒng)的 抗 干擾 性 ，并 且支 持35． 5V 的電壓范圍，使系統(tǒng)設(shè)計(jì)更靈活、方便． DSl8820 內(nèi)部 ROM 中的 64 位序列號(hào)是出廠前用激光光刻寫(xiě)好的，它可以看作是該 DSl8820 的地址序列碼． 64 位光刻 ROM 的排列是：開(kāi)始 8 位是產(chǎn)品類(lèi)型標(biāo)號(hào)，DSl8820 的產(chǎn)品系列碼固定為 28H；接著的 48 位是該 DSl8820 自身的序列號(hào)，而這 48 位序列號(hào)為全球唯一的，最后 8 位是前面 56 位的循環(huán)冗余校驗(yàn)碼．利用 DSl8820 ROM 中的序列號(hào)作為 1 一 Wire 網(wǎng)絡(luò)中的地址，唯一標(biāo)識(shí)一個(gè)傳感器，這樣就可以實(shí)現(xiàn)一根總線上掛接多個(gè)DSl8820 的目的． 根據(jù) Dallas 公司提供的 DSl8820 資料，每根單線總線上最多可以掛 248 個(gè) l— Wire 器件