DS18B20 / DS1822 Temperatūras zondes kabelis

DS18B20/DS1822 ir plaši izmantots digitālais temperatūras sensors. Tā izeja ir digitālais signāls, kam ir maza izmēra īpašības, zemas aparatūras virs galvas, Spēcīga pret savstarpējo spēju spējas un augsta precizitāte. The DS18B20 digital temperature sensor is easy to wire and can be used in a variety of situations after being packaged, piemēram, cauruļu tips, vītņots tips, magnēta adsorbcijas tips, and stainless steel packaging type. Ir dažādi modeļi, ieskaitot LTM8877, LTM8874 un tā tālāk. 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" tehnoloģija, 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 "vienas līnijas autobuss" saskarne, 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 "vienas līnijas autobuss", 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, utt.. 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-bitu fotolitogrāfijas ROM, temperatūras sensors, non-volatile temperature alarm trigger TH and TL, configuration register.
The pin arrangement of DS18B20 is as follows
DQ ir digitālā signāla ievades/izvades spaile; GND ir barošanas zemējums; VDD ir ārējā barošanas avota ievades spaile (iezemēts parazītu strāvas vadu režīmā).
The 64-bit serial number in the photo etched ROM is photo etched before leaving the factory. To var uzskatīt par DS18B20 adreses sērijas kodu. 64 bitu fotolitogrāfijas ROM izkārtojums ir: pirmais 8 biti (28H) ir produkta veida numurs, the next 48 biti ir paša DS18B20 sērijas numurs, 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, lai vienai kopnei varētu pievienot vairākus DS18B20.
Temperatūras sensors DS18B20 var pabeigt temperatūras mērīšanu. Kā piemēru ņemiet 12 bitu konvertēšanu: it is provided in the form of a 16-bit sign-extended two's complement reading, izteikts 0,0625°C/LSB formā, kur S ir zīmes bits.
Šie ir 12 bitu dati, kas iegūti pēc 12 bitu konvertēšanas, kas tiek glabāts divās 8 bitu RAM 18B20. Pirmais 5 bits in binary are sign bits if the measured temperature is greater than 0. Šie 5 biti ir 0. Vienkārši reiziniet izmērīto vērtību ar 0.0625 lai iegūtu faktisko temperatūru. Ja temperatūra ir mazāka par 0, šie 5 biti ir 1, un izmērītā vērtība ir jāapgriež, plus 1, un pēc tam reizināts ar 0.0625 lai iegūtu faktisko temperatūru.
Piemēram, +125℃ digitālā izeja ir 07D0H, digitālā izeja +25,0625℃ ir 0191H, digitālā izeja -25,0625 ℃ ir FE6FH, un digitālā izeja -55 ℃ ir FC90H.

External digital temperature sensor

DS18B20 Temperature Sensor with USB Connector

DS18B20 temperatūras sensors ūdensnecaurlaidīgs zondes stieples instalācija

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 un struktūru reģistri.
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. Devītais baits ir atlaišanas pārbaudes baits.
The meaning of each bit of this byte is as follows:
TM R1 R0 1 1 1 1 1
Apakšējie pieci biti vienmēr ir 1. TM is the test mode bit, ko izmanto, lai iestatītu, vai DS18B20 ir darba vai testa režīmā. Šis bits ir iestatīts uz 0 kad DS18B20 atstāj rūpnīcu, un lietotājiem nevajadzētu to mainīt. R1 un R0 tiek izmantoti, lai iestatītu izšķirtspēju, kā parādīts nākamajā tabulā: (DS18B20 ir iestatīts uz 12 biti, kad tie tiek nosūtīti no rūpnīcas)
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
Saskaņā ar DS18B20 sakaru protokolu, the host must go through three steps to control DS18B20 to complete the temperature conversion: DS18B20 ir jāatiestata pirms katras lasīšanas un rakstīšanas, and a ROM command is sent after the reset is successful. Beidzot, the RAM command is sent so that the DS18B20 can be operated as scheduled. Atiestatīšanai ir nepieciešams galvenais CPU, lai novilktu datu līniju uz leju 500 mikrosekundes un pēc tam atlaidiet to. After receiving the signal, DS18B20 waits for about 16 līdz 60 mikrosekundes, un pēc tam izsūta zemu impulsu 60 līdz 240 mikrosekundes. Galvenais CPU saņem šo signālu, lai norādītu uz veiksmīgu atiestatīšanu.