數(shù)字溫度傳感器外文翻譯6

1、<p><b>　　英文參考資料</b></p><p>　　The DS18B20 Digital Thermometer provides 9 to 12–bit centigrade temperature measurements and has an alarm function with nonvolatile user-programmable upper and l

2、ower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of –55&

3、#176;C to +125°C and is accurate to 0.5 C over the range of –10°C to +85°C. In addition, the DS18B20 can derive power direc</p><p>　　Each DS18B20 has a unique 64-bit serial code, which allows

4、 multiple DS18B20s to function on the same 1–wire bus; thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area. Applications that can benefit from this feature include HVAC env

5、ironmental controls, temperature monitoring systems inside buildings, equipment or machinery, and process monitoring and control systems.</p><p><b>　　OVERVIEW</b></p><p>　　The 64-bit

6、 ROM stores the device’s unique serial code. The scratchpad memory contains the 2-byte temperature register that stores the digital output from the temperature sensor. In addition, the scratchpad provides access to the 1

7、-byte upper and lower alarm trigger registers (T and T ), and the 1-byte configuration H L register. The configuration register allows the user to set the resolution of the temperature-to-digital conversion to 9, 10, 11,

8、 or 12 bits. The T, T and configuration registers </p><p>　　Another feature of the DS18B20 is the ability to operate without an external power supply. Power is instead supplied through the 1-Wire pull up res

9、istor via the DQ pin when the bus is high. The high bus signal also charges an internal capacitor (C ), which then supplies power to the device when the bus is PP low. This method of deriving power from the 1-Wire bus is

10、 referred to as “parasite power.” As an alternative, the DS18B20 may also be powered by an external supply on VDD</p><p>　　OPERATION — MEASURING TEMPERATURE</p><p>　　The core functionality of th

11、e DS18B20 is its direct-to-digital temperature sensor. The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5 C, 0.25 C, 0.125 C, and 0.0625 C, respecti

12、vely. The default resolution at power-up is 12-bit. The DS18B20 powers-up in a low-power idle state; to initiate a temperature measurement and A-to-D conversion, the master must issue a Convert T [44h] command. Following

13、 the conversion, the resulting t</p><p>　　POWERING THE DS18B20</p><p>　　The DS18B20 can be powered by an external supply on the VDD pin, or it can operate in “parasite power” mode, which allows

14、the DS18B20 to function without a local external supply. Parasite power is very useful for applications that require remote temperature sensing or that are very space constrained. DS18B20’s parasite-power control circui

15、try, which “steals” power from the 1-Wire bus via the DQ pin when the bus is high. The stolen charge powers the DS18B20 while the bus is high, and some of the</p><p>　　DS18B20數(shù)字溫度傳感器提供9-12位的分辨率而且還有一種報警功能，它內(nèi)部

16、有非易失的用戶可編程的單元用來設(shè)置溫度的上限和下限。DS18B20通過一總線技術(shù)來通信，只需要一根數(shù)據(jù)線就可以與單片機進行通信。它可以檢測的范圍是-55°C 到+125°C，而且在–10°C 到+85°C.范圍內(nèi)它的精確度是0.5 C。此外DS18B20能夠通過數(shù)據(jù)線驅(qū)動，也就是通過數(shù)據(jù)線傳遞能量，這樣就可以避免另外設(shè)計電源電路和電源線了。</p><p>　　每個DS18

17、B20都有唯一的64位序列號?？梢园讯鄠€DS18B20連接在一根數(shù)據(jù)線上，通過這個序列號可以操作響應(yīng)的溫度傳感器。這樣很容易就可以實現(xiàn)一個單片機控制多個溫度傳感器。HVAC環(huán)境控制器和溫度控制器系統(tǒng)都應(yīng)用該傳感器實現(xiàn)了很好的功能。</p><p>　　正如上面所說的64位的ROM中存儲這溫度傳感器的唯一序列號。RAM中存儲著兩個字節(jié)的溫度值，這兩個字節(jié)的數(shù)據(jù)將來要通過數(shù)據(jù)總線傳到單片機那里。此外，暫時寄存器還和一

18、個字節(jié)的上限、下限寄存器相連，同時也和一個字節(jié)的配置字相連。這個配置寄存器允許用戶設(shè)置溫度傳感器的分辨率在9、10、11、12這四個數(shù)之間。上下限寄存器和配置寄存器都是用非可易失性的材料做的，所以在掉電之后也不會丟失數(shù)據(jù)。該溫度傳感器通過達拉斯公司獨特的單總線技術(shù)通過一根數(shù)據(jù)線實現(xiàn)和單片機的交互。數(shù)據(jù)線也就是總線需要一個比較小的上拉電阻，因為所有的信號都是通過總線來傳輸?shù)模@根總線有三種狀態(tài)，在單總線系統(tǒng)中，單片機也就是主設(shè)備通過溫度傳

19、感器的唯一的64位碼來識別和定位傳感器。因為每個但單總線設(shè)備都有一個唯一的64位的識別碼，所以主機可以連接的從設(shè)備理論上說是沒有數(shù)量限制的。</p><p>　　DS18B20另一個特征是它不需要額外的供電系統(tǒng)。電源是通過單總線系統(tǒng)中的DQ管腳傳入的，當(dāng)這個管腳是高電壓時供電。而當(dāng)DQ為低電平時，傳感器就不工作了？當(dāng)然不是了，在溫度傳感器的內(nèi)部有一個電容，當(dāng)DQ為高電平時充電，當(dāng)DQ為低電平時放電，放出來的電給傳

20、感器供電。當(dāng)然如果不只使用溫度傳感器的一個管腳的話，也可以由額外供電，也就是通過傳感器的VDD管腳，給它提供+5V的電壓就可以使DS18B20正常工作了。</p><p>　　DS18B20的核心部位是其可以直接將外界溫度信息直接轉(zhuǎn)換成數(shù)字信號的溫度傳感器。該溫度傳感器是可以用戶設(shè)置的，有9位、10位、11位和12位的分辨率，分別對應(yīng)0.5 C, 0.25 C, 0.125 C,和 0.0625 C,的增量，也就

21、是說數(shù)字每增加一溫度增加的值。默認情況下是設(shè)置成12位模式的。為了能夠初始化溫度傳感器和使其內(nèi)部的模數(shù)轉(zhuǎn)換電路工作，主設(shè)備也就是單片機需要給DS18B20發(fā)出轉(zhuǎn)換命令（即向DS18B20傳送44H）。在傳感器接收到命令之后，并作出反應(yīng)后，溫度值被存儲在溫度傳感器內(nèi)部的兩字節(jié)的溫度寄存器中，這兩個字節(jié)在斷電后會丟失數(shù)據(jù)，然后溫度傳感器恢復(fù)等待命令狀態(tài)（即空閑狀態(tài)）。如果DS18B20是由額外電源供電的話，那么DS18B20會在正在轉(zhuǎn)換時保

22、持低電平，而完成轉(zhuǎn)換之后就會保持高電平了。如果DS18B20是寄生供電的話，由于在傳感器轉(zhuǎn)換期間需要比較大量的電能，所以就不能夠支持上訴的功能了。溫度傳感器中要輸出的溫度數(shù)據(jù)單位是按照攝氏溫度來的，如果要轉(zhuǎn)換成華氏溫度的話就需要用戶自己做一個轉(zhuǎn)換表了。溫度值在DS18B20中是以兩字節(jié)的補碼形式存儲在溫度傳感器中的。符</p><p>　　DS18B20既可以通過VDD管腳來提供額外的電源，也可以通過寄生電源的方

23、式來為其自身供電。寄生電源對于要求要求遠距離溫度檢測的應(yīng)用或者是那些非常惡劣的環(huán)境下的一個用來說是非常合適的。溫度傳感器的寄生電源是在DQ管腳為高電壓的時候存儲電量來為以后DQ為低的時候供電。而且當(dāng)傳感器工作在寄生電源的模式下時，VDD管腳一定要接地，不然就會不能判定究竟是在什么模式在工作了。當(dāng)DS18B20工作在寄生電源模式時，單總線和CPP能夠為其大部分的操作提供足夠的電源。而當(dāng)DS18B20進行溫度轉(zhuǎn)換或?qū)?shù)據(jù)從易失性存儲介質(zhì)中拷