DS18B20 / DS1822 temperatuursondekabel

DS18B20/ DS1822 is 'n algemeen gebruikte digitale temperatuursensor. Die uitset daarvan is 'n digitale sein, wat die kenmerke van klein grootte het, Lae hardeware oorhoofse, Sterk anti-interferensievermoë en hoë presisie. Die DS18B20 digitale temperatuursensor is maklik om te bedraad en kan in 'n verskeidenheid situasies gebruik word nadat dit verpak is, soos pyp tipe, draadtipe, magneet adsorpsie tipe, and stainless steel packaging type. Daar is verskeie modelle, insluitend LTM8877, LTM8874 en so aan. 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" tegnologie, 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 "eenlyn bus" koppelvlak, 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 "eenlyn bus", 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, ens. 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-bietjie fotolitografie ROM, temperatuur sensor, non-volatile temperature alarm trigger TH and TL, configuration register.
The pin arrangement of DS18B20 is as follows
DQ is die digitale sein inset/uitset terminaal; GND is die kraggrond; VDD is die eksterne kragtoevoer insetterminaal (geaard in die parasitiese kragbedradingsmodus).
The 64-bit serial number in the photo etched ROM is photo etched before leaving the factory. Dit kan beskou word as die adresreekskode van die DS18B20. Die rangskikking van die 64-bis fotolitografiese ROM is: die eerste 8 stukkies (28H) is die produk tipe nommer, die volgende 48 bisse is die reeksnommer van die DS18B20 self, en die laaste 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, sodat verskeie DS18B20's aan een bus gekoppel kan word.
Die temperatuursensor in DS18B20 kan die meting van temperatuur voltooi. Neem 12-bis omskakeling as 'n voorbeeld: it is provided in the form of a 16-bit sign-extended two's complement reading, uitgedruk in die vorm van 0,0625°C/LSB, waar S die teken bietjie is.
Dit is die 12-bis data verkry na 12-bis omskakeling, wat in twee 8-bis RAM's van 18B20 gestoor word. Die eerste 5 bits in binary are sign bits if the measured temperature is greater than 0. Hierdie 5 stukkies is 0. Vermenigvuldig net die gemete waarde met 0.0625 om die werklike temperatuur te kry. As die temperatuur laer is as 0, hierdie 5 stukkies is 1, en die gemete waarde moet omgekeer word, plus 1, en dan vermenigvuldig met 0.0625 om die werklike temperatuur te kry.
Byvoorbeeld, die digitale uitset van +125℃ is 07D0H, die digitale uitset van +25.0625℃ is 0191H, die digitale uitset van -25.0625 ℃ is FE6FH, en die digitale uitset van -55 ℃ is FC90H.

External digital temperature sensor

DS18B20 Temperature Sensor with USB Connector

DS18B20 temperatuur sensor waterdigte sonde draad harnas

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 en struktuurregisters.
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
Die onderste vyf stukkies is altyd 1. TM is the test mode bit, wat gebruik word om te bepaal of die DS18B20 in werkmodus of toetsmodus is. Hierdie bietjie is ingestel op 0 wanneer DS18B20 die fabriek verlaat, en gebruikers moet dit nie verander nie. R1 en R0 word gebruik om die resolusie te stel, soos in die volgende tabel getoon: (DS18B20 is ingestel op 12 stukkies wanneer dit van die fabriek af gestuur word)
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. Uiteindelik, 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 na 60 mikrosekondes, and then sends out a low pulse of 60 na 240 mikrosekondes. Die hoof-SVE ontvang hierdie sein om suksesvolle terugstelling aan te dui.