DS18B20 is a commonly used digital temperature sensor, which has the characteristics of small size, low hardware overhead, strong anti-interference ability and high precision. [1] The DS18B20 digital temperature sensor is easy to wire and can be used in a variety of occasions after being packaged, such as pipeline type, threaded type, magnet adsorption type, stainless steel package type, and various models, including LTM8877, LTM8874 and so on.

mainly changes its appearance according to different applications. The packaged DS18B20 can be used for cable trench temperature measurement, blast furnace water circulation temperature measurement, boiler temperature measurement, machine room temperature measurement, agricultural greenhouse temperature measurement, clean room temperature measurement, ammunition warehouse temperature measurement and other non-limiting temperature occasions. Wear-resistant and anti-collision, small size, easy to use, various packaging forms, suitable for various small space equipment digital temperature measurement and control fields.

Ds18b20 technical performance description

①, the unique single-wire interface mode, when DS18B20 is connected with the microprocessor, only one port line is needed to realize the two-way communication between the microprocessor and DS18B20.

②, the temperature measurement range is -55℃～+125℃, the inherent temperature measurement error (note that it is not the resolution, the previous error here) is 1℃.

③. Support multi-point networking function. Multiple DS18B20s can be connected in parallel on only three wires, and only 8 can be connected in parallel to achieve multi-point temperature measurement. If the number is too large, the voltage of the power supply will be too low, resulting in signal transmission The instability.

④, working power supply: 3.0~5.5V/DC (data line parasitic power supply is possible)

⑤, no external components are needed in use

⑥, the measurement results are serially transmitted in the form of 9~12 digits

⑦, stainless steel protection tube diameter Φ6

⑧, suitable for temperature measurement of DN15~25, DN40~DN250 various medium industrial pipelines and equipment in narrow spaces

⑨, standard installation thread M10X1, M12X1.5, G1/2" optional

⑩, PVC cable outlet directly or German ball junction box outlet, easy to connect with other electrical equipment.

Ds18b20 application range

This product is suitable for temperature measurement and control fields such as freezer, granary, storage tank, telecommunications room, power room, cable trunking and so on. Temperature measurement and control of industrial equipment in small spaces such as bearings, cylinders, textile machinery, air conditioners, etc. Automobile air conditioners, refrigerators, freezers, and medium and low temperature drying boxes, etc. Heating/cooling pipe heat metering, household heat energy metering for central air-conditioning, and temperature measurement and control in industrial fields.

Ds18b20 wiring method

is facing the flat side, the left is negative and the right is positive. Once the connection is reversed, it will immediately heat up and may burn! At the same time, the reverse connection is also the reason that the sensor always displays 85°C. In actual operation, if the positive and negative are reversely connected, the sensor immediately heats up, and the LCD screen cannot display the reading. After the positive and negative are connected, it will display 85℃. In addition, if a 51 single-chip microcomputer is used, the middle pin must be connected to a 4.7K-10K pull-up resistor, otherwise, due to the high level cannot be input/output normally, it will either display 85°C immediately after power on, or use it for several months After that, the temperature jumped randomly between 85°C and the normal value.

ds18b20 advantages and disadvantages analysis

advantages

1) When the single-bus interface is used to connect to the microprocessor, only one port is needed to realize the two-way communication between the microprocessor and DS18B20. The single bus has good economy and strong anti-interference ability.

2) Wide measuring temperature range and high measuring accuracy. The measurement range of DS18B20 is -559C~+125%C; in the range of -10~+85"C, the accuracy is t0.5"C.

3) Temperature measurement can be achieved without any peripheral components during use.

4) Multi-point networking function. Multiple DS18B20s can be connected in parallel on the only three wires to achieve multi-point temperature measurement.

5) Flexible power supply mode. DS18B20 can obtain power from the data line through the internal parasitic circuit. Therefore, when the time sequence on the data line meets certain requirements, the external power supply can be omitted, which makes the system structure simpler and more reliable.

6) The measurement parameters can be configured. The measurement resolution of DS18B20 can be set to 9~12 digits by program.

7) Negative pressure characteristics. When the polarity of the power supply is reversed, the thermometer will not be burnt due to heat, but it will not work normally.

8) Power-down protection function. The DS18B20 has an EEPROM internally. After the system is powered off, it can still save the resolution and alarm temperature settings.

Disadvantages

1) It is more difficult to understand the program involving ROM search when using multiple single buses

2) Generally, the accuracy can only meet the general requirements