DS18B20 / DS1822 温度プローブケーブル

DS18B20/ DS1822は、一般的に使用されるデジタル温度センサーです. その出力はデジタル信号です, サイズが小さいのが特徴です, ハードウェアのオーバーヘッドが低い, 強力な抗干渉能力と高精度. The DS18B20 digital temperature sensor is easy to wire and can be used in a variety of situations after being packaged, パイプタイプなど, ねじ込みタイプ, マグネット吸着タイプ, and stainless steel packaging type. 色々なモデルがあります, LTM8877を含む, LTM8874など. As a digital temperature sensor, the DS18B20 does not require any external components when measuring temperature. It can directly output the measured temperature value of 9~12 bits (including sign bit). The temperature measurement range is -55~+125℃. The measurement accuracy is ±0.5℃ in the range of -10~+85℃, and the output measurement resolution is adjustable, up to 0.0625℃. Supporting "single-wire bus" テクノロジー, only one general-purpose I/O port is required to complete communication with the microcontroller. The on-site temperature is directly transmitted digitally via a "single-wire bus", which greatly improves the system's anti-interference capability.

DS18B20, DS1822 "One-line bus" digital temperature sensor Same as DS1820. DS18B20 also supports "単線バス" インタフェース, and the measurement temperature range is -55°C~+125°C, and the accuracy is ±0.5°C in the range of -10~+85°C. The accuracy of the DS1822 is ±2°C. The on-site temperature is directly transmitted digitally via the "単線バス", which greatly improves the system's anti-interference capability. Suitable for on-site temperature measurement in harsh environments, such as environmental control, equipment or process control, temperature measurement consumer electronics, 等. The new product supports a voltage range of 3V~5.5V, making system design more flexible and convenient. And the new generation of products is cheaper and smaller. Features of DS18B20 and DS1822 DS18B20 can be programmed with a resolution of 9~12 bits and an accuracy of ±0.5°C. Optional smaller package, wider voltage range. The resolution setting and the user-set alarm temperature are stored in EEPROM and are still saved after power off. The performance of DS18B20 is the best among the new generation products! The price-performance ratio is also excellent! The DS1822 is software compatible with the DS18B20 and is a simplified version of the DS18B20. The EEPROM that stores user-defined alarm temperature and resolution parameters is omitted, and the accuracy is reduced to ±2°C. It is suitable for applications with low performance requirements and strict cost control. It is an economical product. Following the early products of the "One Line Bus", the DS1820 opens up a new concept in temperature sensor technology. DS18B20 and DS1822 provide more choices in voltage, characteristics and packaging, allowing us to build an economical temperature measurement system that suits us.

Internal structure of ds18b20 temperature probe
The internal structure of DS18B20 mainly consists of four parts:
64-ビットフォトリソグラフィROM, 温度センサー, non-volatile temperature alarm trigger TH and TL, configuration register.
The pin arrangement of DS18B20 is as follows
DQは、デジタル信号入力/出力端子です; GNDは電力場です; VDDは外部電源入力端子です (寄生電源配線モードで接地).
The 64-bit serial number in the photo etched ROM is photo etched before leaving the factory. DS18B20のアドレスシリアルコードとみなすことができます。. 64ビットフォトリソグラフィーROMの構成は次のとおりです。: 最初 8 ビット (28H) は製品型番です, 次は 48 ビットは DS18B20 自体のシリアル番号です, and the last 8 bits are the previous 56-bit cyclic redundancy check code (CRC=X8 +X5+X4+1). The purpose of the photolithography ROM is to make each DS18B20 different, 複数のDS18B20を1つのバスに接続できるように.
DS18B20 の温度センサーは温度の測定を完了できます。. 12ビット変換を例に挙げます: it is provided in the form of a 16-bit sign-extended two's complement reading, 0.0625℃/LSBの形式で表される, ここで、Sはサインビットです.
12ビット変換後の12ビットデータです, 18B20 の 2 つの 8 ビット RAM に保存されます。. 最初 5 bits in binary are sign bits if the measured temperature is greater than 0. These 5 ビットはです 0. 測定値を掛けるだけです 0.0625 実際の温度を取得します. 温度が少ない場合 0, これら 5 ビットはです 1, 測定値を反転する必要があります, プラス 1, そして、それを掛けます 0.0625 実際の温度を取得します.
例えば, +125℃のデジタル出力は07d0hです, +25.0625のデジタル出力は0191Hです, -25.0625℃のデジタル出力はFE6FHです, -55℃のデジタル出力はFC90Hです.

External digital temperature sensor

DS18B20 Temperature Sensor with USB Connector

DS18B20 温度センサー防水プローブワイヤーハーネス

DS18B20 temperature sensor memory
The internal memory of the DS18B20 temperature sensor includes a high-speed scratchpad RAM and a non-volatile electrically erasable E2RAM, which stores high-temperature and low-temperature triggers TH, TL と構造レジスタ.
The temporary storage memory contains 8 consecutive bytes, the first two bytes are the measured temperature information. The content of the first byte is the lower eight bits of the temperature. The second byte is the high eight bits of the temperature. The third and fourth bytes are volatile copies of TH and TL, and the fifth byte is a volatile copy of the architectural register. The contents of these three bytes are refreshed at each power-on reset. The sixth, seventh, and eighth bytes are used for internal calculations. The ninth byte is the redundancy check byte.
The meaning of each bit of this byte is as follows:
TM R1 R0 1 1 1 1 1
下位 5 ビットは常に 1. TM is the test mode bit, DS18B20 が動作モードかテストモードかを設定するために使用されます。. このビットは次のように設定されます。 0 DS18B20が工場から出荷されるとき, ユーザーはそれを変更しないでください. R1 と R0 は解像度の設定に使用されます, 次の表に示すように: (DS18B20は次のように設定されています 12 工場出荷時のビット)
Resolution setting table:
R1 R0 Resolution Temperature Maximum Conversion Time
0 0 9 bits 93.75ms
0 1 10 bits 187.5ms
1 0 11 bits 375ms
1 1 12 bits 750ms
According to the communication protocol of DS18B20, the host must go through three steps to control DS18B20 to complete the temperature conversion: DS18B20 must be reset before each read and write, and a ROM command is sent after the reset is successful. ついに, the RAM command is sent so that the DS18B20 can be operated as scheduled. Reset requires the main CPU to pull the data line down for 500 microseconds and then release it. After receiving the signal, DS18B20 waits for about 16 に 60 マイクロ秒, and then sends out a low pulse of 60 に 240 マイクロ秒. The main CPU receives this signal to indicate successful reset.