ds18b20 temperature sensor datasheet - The DS18B20 Digital Thermometer provides 9 to 12-bit (configurable) temperature readings which indicate the temperature of the device.
Information is sent to/from the DS18B20 over a 1-Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS18B20.
Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source. Because each DS18B20 contains a unique silicon serial number, multiple DS18B20s can exist on thesame 1-Wire bus.
This allows for placing temperature sensors in many different places. Applications where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings,equipment or machinery, and process monitoring and control.
The block diagram shows the major components of the DS18B20. The DS18B20 has four main data components:
As an alternative, the DS18B20 may also bepowered from an external 3 volt - 5.5 volt supply.
Communication to the DS18B20 is via a 1-Wire port. With the 1-Wire port, the memory and control functions will not be available before the ROM function protocol has been established.
The master must first provide one of five ROM function commands:
After a ROM function sequence has been successfully executed, the memory and control functions are accessible and the master may then provide any one of the six memory and control function commands.
One control function command instructs the DS18B20 to perform a temperature measurement. The result of this measurement will be placed in the DS18B20’s scratch-pad memory, and may be read by issuing a memory function command which reads the contents of the scratchpad memory.
The temperature alarm triggers TH and TL consist of 1 byte EEPROM each. If the alarm search command is not applied to the DS18B20, these registers may be used as general purpose user memory.
The scratchpad also contains a configuration byte to set the desired resolution of the temperature to digital conversion. Writing TH, TL, and the configuration byte is done using a memory function command. Read access to these registers isthrough the scratchpad. All data is read and written least significant bit first.
The most significant bit of TH or TL directly corresponds to the sign bit of the 16-bittemperature register.
If the result of a temperature measurement is higher than TH or lower than TL, an alarm flag inside the device is set. This flag is updated with every temperature measurement.
As long as the alarm flag is set, the DS18B20 will respond to the alarm search command. This allows many DS18B20s to be connected in parallel doing simultaneous temperature measurements.
If somewhere the temperature exceeds the limits, the alarming device(s) can be identified and read immediately without having to read non-alarming devices.
In this video We will do a quick review on both DHT22 Temperature and Humidity and DS18B20 Temperature 1-Wire sensors, and We will compare them to give you an idea on which one fits better in your projects.
For more details you can download DS18B20 Temperature Sensor datasheet here.
Information is sent to/from the DS18B20 over a 1-Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS18B20.
Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source. Because each DS18B20 contains a unique silicon serial number, multiple DS18B20s can exist on thesame 1-Wire bus.
This allows for placing temperature sensors in many different places. Applications where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings,equipment or machinery, and process monitoring and control.
Features of DS18B20 Programmable Resolution 1-Wire Digital Thermometer
- Unique 1-Wire interface requires only one port pin for communication
- Multidrop capability simplifies distributed temperature sensing applications
- Requires no external components
- Can be powered from data line. Power supplyrange is 3.0V to 5.5V
- Zero standby power required
- Measures temperatures from -55°C to+125°C. Fahrenheit equivalent is -67°F to+257°F
- ±0.5°C accuracy from -10°C to +85°C
- Thermometer resolution is programmable from 9 to 12 bits
- Converts 12-bit temperature to digital word in750 ms (max.)
- User-definable, nonvolatile temperature alarm settings
- Alarm search command identifies andaddresses devices whose temperature is outside of programmed limits (temperature alarm condition)
- Applications include thermostatic controls,industrial systems, consumer products,thermometers, or any thermally sensitive system.
Overview: DS18B20 Temperature Sensor
The block diagram shows the major components of the DS18B20. The DS18B20 has four main data components:
- 64-bit lasered ROM,
- temperature sensor,
- non volatile temperature alarm triggers TH and TL, and
- a configuration register.
As an alternative, the DS18B20 may also bepowered from an external 3 volt - 5.5 volt supply.
Communication to the DS18B20 is via a 1-Wire port. With the 1-Wire port, the memory and control functions will not be available before the ROM function protocol has been established.
The master must first provide one of five ROM function commands:
- Read ROM,
- Match ROM,
- Search ROM,
- Skip ROM, or
- Alarm Search.
After a ROM function sequence has been successfully executed, the memory and control functions are accessible and the master may then provide any one of the six memory and control function commands.
One control function command instructs the DS18B20 to perform a temperature measurement. The result of this measurement will be placed in the DS18B20’s scratch-pad memory, and may be read by issuing a memory function command which reads the contents of the scratchpad memory.
The temperature alarm triggers TH and TL consist of 1 byte EEPROM each. If the alarm search command is not applied to the DS18B20, these registers may be used as general purpose user memory.
The scratchpad also contains a configuration byte to set the desired resolution of the temperature to digital conversion. Writing TH, TL, and the configuration byte is done using a memory function command. Read access to these registers isthrough the scratchpad. All data is read and written least significant bit first.
DS18B20 - ALARM SIGNALING
After the DS18B20 has performed a temperature conversion, the temperature value is compared to the trigger values stored in TH and TL. Since these registers are 8-bit only, bits 9-12 are ignored for comparison.The most significant bit of TH or TL directly corresponds to the sign bit of the 16-bittemperature register.
If the result of a temperature measurement is higher than TH or lower than TL, an alarm flag inside the device is set. This flag is updated with every temperature measurement.
As long as the alarm flag is set, the DS18B20 will respond to the alarm search command. This allows many DS18B20s to be connected in parallel doing simultaneous temperature measurements.
If somewhere the temperature exceeds the limits, the alarming device(s) can be identified and read immediately without having to read non-alarming devices.
Arduino Temperature Sensor – DHT22 Temperature and Humidity vs. DS18B20 Temperature 1-Wire
DHT22 & DS18B20 Datasheet review and Arduino TutorialIn this video We will do a quick review on both DHT22 Temperature and Humidity and DS18B20 Temperature 1-Wire sensors, and We will compare them to give you an idea on which one fits better in your projects.
For more details you can download DS18B20 Temperature Sensor datasheet here.
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