3 thoughts on “What are the differences between temperature and humidity sensor SHT10 and SHT11?”
Shirley
Mainly different accuracy SHT10 humidity measurement range: 0 to 100%RH; The humidity measurement range: -40 ～ 123.8 ℃; 's humidity measurement accuracy: ± 4.5%RH Temperature measurement accuracy: ± 0.5 ℃
sht11 The humidity measurement range: 0 to 100%RH; n Temperature measurement accuracy: ± 0.4 ℃ The humidity measurement accuracy: ± 3.0%RH
can be universal
sht11 The main characteristics of the temperature and humidity sensor of the temperature of the temperature are as follows: Sensor, signal amplification conditioning, A / D conversion, and I2C bus interface are integrated in a chip (CMOSENSTM technology); ● It can give the full -calibrated relative humidity and temperature value output; ● It has the output function of the dew point value; ● It has excellent long -term stability; ● The output resolution of the humidity value is 14 bits, the temperature value output resolution is 12 digits, and it can be programmed to 12 and 8 digits; ● Small volume (7. 65 × 5.08 × 23.5mm), which can be installed on the surface; ● With a reliable CRC data transmission verification function; ● The calibration coefficient loaded in the tablet can ensure 100 % interchangeability; ● The power supply voltage range is 2.4 ～ 5.5V; ● current consumption, 550 μA during measurement, average of 28 μA, and 3 μA during sleep.
The temperature and humidity sensor of SHT11 uses SMD (LCC) surface packaging form. The arranges of the tube foot are shown in Figure 1, and its pin explains as follows: (1) GND: grounding end; (2) Data : Two -way serial data cable; (3) SCK: serial clock input; (4) VDD power supply end: 0.4 ～ 5.5V power supply side; (5-8) NC: empty pipe foot.
3 The humidity detection of the working principle of SHT11 uses a capacitive structure, and uses a "miniature structure" to detect the electrode system and polymer coverage layer with different protection to form a capacitor of the sensor chip. In addition to the original characteristics of the device, it can also resist the impact from the outside world. Because it combines the temperature sensor and the humidity sensor, it constitutes a single individual, so the measurement accuracy is high and can be accurately obtained, and at the same time, it will not produce errors caused by changes in temperature gradient between temperature and humidity sensors. CMOSENSTM technology not only combines temperature and humidity sensors, but also integrates signal amplifiers, mold / number converters, calibration data memory, standard I2C bus and other circuits in one chip. The internal structure box diagram of the SHT11 sensor is shown in Figure 2. Each sensor of SHT11 is calibrated in extremely accurate humidity rooms. The calibration coefficient of the SHT11 sensor pre -existence in OTP memory. The calibrated relative humidity and temperature sensor are connected to a 14 -bit A / D converter, which can send the conversion digital temperature humidity value to the second -line I2C bus device, thereby converting the digital signal into a serial number that meets the I2C bus protocol Signal.
It because the sensor and the circuit are partially combined, the sensor has much better performance than other types of humidity sensors. The first is that the increase in the signal strength of the sensor enhances the anti -interference performance of the sensor, ensuring the long -term stability of the sensor, and the completion of the A / D conversion at the same time reduces the sensitivity of the sensor to interference noise. Secondly, the calibration data loaded in the sensor chip ensures that each humidity sensor has the same function, that is, 100 % interchangeability. Finally, the sensor can be connected directly with any type of microprocessor and microcontroller system through the I2C bus, thereby reducing the hardware cost of the interface circuit and simplifying the interface method. 3.1 Output features (1) Humidity value output SHT11 can directly output digital measurement humidity values through the I2C bus. The relative humidity digital output characteristic curve is shown in Figure 3. It can be seen from Figure 3 that the output characteristics of the SHT11 are certain non -linear. In order to compensate the non -linearity of the humidity sensor, the humidity value can be corrected according to the following formula: Rhlinear = C1 C2SORH C3SORH2 formula, SORH is the sensor's relative humidity measurement value, the coefficient value of the value As follows: 12 digits: SORH: C1 = -4, C2 = 0.0405, C3 = -2.8 × 10-68 bits: SORH: C1 = -4, C2 = 0.648, C3 = -7.2 × 10-4 (2) Temperature value output. Since the linearness of the SHT11 temperature sensor is very good, the following formula can be used to convert the temperature digital output to the actual temperature value: T = D1 D2SOT When the power supply voltage is 5V, and the resolution of the temperature sensor is 14 bits of 14 bits At this time, D1 = -40 D2 = 0.01, when the resolution of the temperature sensor is 12 bits, D1 = -40 D2 = 0.04. (3) The dew point value of the dew point calculation can be obtained according to the relative humidity and temperature value. The specific calculation formula is as follows: logew = (0.66077 7.5T / (237.3 t) [log10 (RH) -2] dp = [(0.66077 -Logew) × 237.3] / (logew -8.16077) 3.2 commands and interface timing SHT11 sensors have 5 user commands. Command sequence and command time order.
Table 1 SHT11 sensor command list command coding instructions measurement temperature 00011 temperature measurement measurement humidity 00101 humidity measurement n read register status 001111 " Read the "Status register Write the status of the register 00110" Write "status register Soft start 11110 restart chip, remove the error record of the status recorder 11 milliseconds, enter the next command (1) Transmission starts starting starts starting starts starts. When initialized transmission, the "transmission start" command should be issued first. This command can change the DATA from a high level to a low level when the SCK is high, and the DATA is raised when the next SCK is high. Including three addresses (currently only supports "000") and 5 commands. When the ACK position of the data foot is at a low potential, it means that the SHT11 is correctly received by the command. , The following signal order will reset the serial port: that is, when the DATA cable is at high electricity, it triggers SCK more than 9 times (including 9 times). After that, a "transmission start" command should be issued.
Table 2 Table 2 SHT11状态寄存器类型及说明位类型说明缺省rn7 保留0 rn6 读工检限（低电压检查） X rn5 保留0 rn4 保留0 rn3 只用于Tests, you cannot use 0 2 read/write heating 0 levels 1 Reading/write do not download 0 download 0 read/write '1' = 8 -bit relative humidity, 12 -bit temperature Resolution. '0 '= 12 -bit relative humidity, 14 -bit humidity resolution 0 12 -bit relative humidity, 14 -bit humidity (3) After the sequence of temperature and humidity measurement is issued, the control is issued The device has to wait until the measurement is complete. Use the resolution measurement of 8/12/14 bits requires about 11/55 / 210ms. To indicate that the measurement is completed, the SHT11 will make the data cable lower. At this time, the controller must restart the SCK. Then transmit two -byte measurement data and 1 byte CRC verification. The controller must confirm each byte by reducing the data to low, and all the amount Calculated from the right, MSB ranked first. The communication stopped after confirming the CRC data bit. If there is no CRC -8 verification, the controller will keep ACK stop communication after the measurement data LSB is measured. After the measurement and communication are completed, the SHT11 will automatically return to the sleep mode. It should be noted that the operating frequency of the SHT11 is lower than 0.1 ° C at this time cannot be greater than 15 % of the calibration value (such as 12 -bit accuracy, a maximum measurement of up to 3 times per second). The timing corresponding to the measurement temperature and humidity command is shown in Figure 4.
3.3 The register configuration of some of the advanced functions in the SHT11 sensor is achieved by a state register. The types and descriptions of the registers are listed in Table 2. The functional description of the register -related bit below: (1) After the heating is connected to the heating switch in the chip, the temperature of the sensor increases by about 5 ° C, which increases the power consumption to 8mA ＠ 5V. The heating purposes are as follows: ● By comparing the temperature and humidity before and after starting the heater, the functions of the sensor can be correctly distinguished; ● In the environment with a relatively high humidity, the sensor can avoid condensation by heating. (2) The low voltage detection SHT11 can detect whether the VDD voltage is less than 2.45V during work, and the accuracy is ± 0.1V. (3) Download the calibration coefficient In order to save energy and increase speed, OTP must be re -downloaded the calibration coefficient before each measurement, so that each measurement saves 8.2MS time. (4) Measurement resolution settings The measurement resolution will be reduced from 14 (temperature) and 12 -bit (humidity) to 12 and 8 bits, respectively in high -speed or low power consumption occasions.
4 Application Instructions 4.1 The temperature other than the measurement of the operating conditions will temporarily offset the humidity signal 3 %. Then the sensor will slowly return to the calibration conditions. If the chip is heated for 24 hours to 90 ° C under the environment of humidity less than 5 %, the chip will quickly restore the effects of high relative humidity and high temperature environment. However, extended strength conditions will accelerate the aging of the chip. 4.2 Installation Note Due to the close relationship between the relative humidity of the atmosphere and the temperature, the main point when measured the atmospheric temperature is to keep the sensor and the atmosphere of the same temperature. In order to reduce the thermal conductivity between SHT11 and PCB, the copper wire should be the finest and add a narrow seam to it. At the same time, the sensor should be avoided under strong light or UV. When the sensor is wiring, the SCK and Data signals are parallel and close to each other, or when the signal line is 10cm, the interference information will be generated. At this time, the VDD or GND should be placed between the two sets of signals.
5 Specific application Figure 5 is the interface circuit of AT89C2051 single -chip microcomputer and SHT11. Since AT89C2051 does not have the I2C bus interface, the universal I / O port of the single -chip microcomputer is used to virtual I2C bus, and the P1.0 is used to use the P1.1 port to the virtual clock line, and access on the data end. A 4.7kΩ pull -up resistance, at the same time, connects a 0.1 μF decoupled capacitor on the VDD and GND end. The C51 applications supported with the above hardware circuit are given below. ＃define DATA P1＿1＃define SCK P1＿0＃define ACK 1＃define noACK 0＃define MEASURE_TEMP 0x03 ／／测量温度命令＃define MEASURE_HUMI 0x05 ／／测量湿度命令／／读温湿度数据char s－measure(unsigned char ＊p- value, un-signed char ＊p_checksum, unsigned char mode){unsigned char error＝0;unsigned int i;s_(); ／／传输开始switch(mode){caseTEMP:error＋＝s_write_byte(measure_temp);break;caseHUMI: error = s_write_byte (meAsure_humi); break; default: break;} for (i = 0; i u003C65535; i ) if (data == 0) break; if (data) Reeor = 1; ACK);＊(p_value＋1)＝s_read_byte(ACK);＊p_checksum＝s_read_byte(noACK);return error;}／／温湿度值标度变换及温度补偿void calc_sth15(float ＊p_humidity,float ＊p_tempera-ture){ const float C1 = -4.0; const float C2 = 0.0405; const float C3 = -0.0000028; const float T1 = -0.01; const float T2 = 0.00008; float Rh = × P_Humidity; float; t = × p_; float rh_lin; float th_ture; float T_C; t_c = t × 0.01-40; rh_lin = c3 × rh × rh c2 × rh c1; TRH_TURE = (T_C -25) × (t1 t2 × rh) rh_lin; × p_ = t -c; × p_humidity = rh_ture;} // Calculate the dew point from the relative temperature and humidity charc_dewpoint (float H, Float T) {float logEx, DEW_POINT; logex = 0.6. 6077 7.5 × T / (237.3 T) [log10 (h) -2]; Dew_point = (logex -0.66077) × 237.3 / (0.66077 7.5 -logex); In length, the above program does not give the transmission start, writing line data, and reading byte data function.
6 SHT11 Digital temperature and humidity sensor is integrated into the sensor due to temperature sensor, humidity sensor, signal conditioning, mold / number converter, calibration parameter and I2C bus interface. Therefore, the sensor not only improves the sensor The performance also reduces costs and reduces volume, and is also very convenient to interface with microcontroller. It can be seen that the sensor is an ideal choice for the temperature and humidity testing of embedded systems.
I am the Chinese general generation of SHT. I can tell you responsibly that SHT10 and 11 except for precision except for accuracy, there is no difference. This is their complete exchanges!
Mainly different accuracy
SHT10
humidity measurement range: 0 to 100%RH;
The humidity measurement range: -40 ～ 123.8 ℃;
's humidity measurement accuracy: ± 4.5%RH
Temperature measurement accuracy: ± 0.5 ℃
sht11
The humidity measurement range: 0 to 100%RH;
n Temperature measurement accuracy: ± 0.4 ℃
The humidity measurement accuracy: ± 3.0%RH
can be universal
sht11 The main characteristics of the temperature and humidity sensor of the temperature of the temperature are as follows: Sensor, signal amplification conditioning, A / D conversion, and I2C bus interface are integrated in a chip (CMOSENSTM technology); ● It can give the full -calibrated relative humidity and temperature value output; ● It has the output function of the dew point value; ● It has excellent long -term stability; ● The output resolution of the humidity value is 14 bits, the temperature value output resolution is 12 digits, and it can be programmed to 12 and 8 digits; ● Small volume (7. 65 × 5.08 × 23.5mm), which can be installed on the surface; ● With a reliable CRC data transmission verification function; ● The calibration coefficient loaded in the tablet can ensure 100 % interchangeability; ● The power supply voltage range is 2.4 ～ 5.5V; ● current consumption, 550 μA during measurement, average of 28 μA, and 3 μA during sleep.
The temperature and humidity sensor of SHT11 uses SMD (LCC) surface packaging form. The arranges of the tube foot are shown in Figure 1, and its pin explains as follows: (1) GND: grounding end; (2) Data : Two -way serial data cable; (3) SCK: serial clock input; (4) VDD power supply end: 0.4 ～ 5.5V power supply side; (5-8) NC: empty pipe foot.
3 The humidity detection of the working principle of SHT11 uses a capacitive structure, and uses a "miniature structure" to detect the electrode system and polymer coverage layer with different protection to form a capacitor of the sensor chip. In addition to the original characteristics of the device, it can also resist the impact from the outside world. Because it combines the temperature sensor and the humidity sensor, it constitutes a single individual, so the measurement accuracy is high and can be accurately obtained, and at the same time, it will not produce errors caused by changes in temperature gradient between temperature and humidity sensors. CMOSENSTM technology not only combines temperature and humidity sensors, but also integrates signal amplifiers, mold / number converters, calibration data memory, standard I2C bus and other circuits in one chip. The internal structure box diagram of the SHT11 sensor is shown in Figure 2. Each sensor of SHT11 is calibrated in extremely accurate humidity rooms. The calibration coefficient of the SHT11 sensor pre -existence in OTP memory. The calibrated relative humidity and temperature sensor are connected to a 14 -bit A / D converter, which can send the conversion digital temperature humidity value to the second -line I2C bus device, thereby converting the digital signal into a serial number that meets the I2C bus protocol Signal.
It because the sensor and the circuit are partially combined, the sensor has much better performance than other types of humidity sensors. The first is that the increase in the signal strength of the sensor enhances the anti -interference performance of the sensor, ensuring the long -term stability of the sensor, and the completion of the A / D conversion at the same time reduces the sensitivity of the sensor to interference noise. Secondly, the calibration data loaded in the sensor chip ensures that each humidity sensor has the same function, that is, 100 % interchangeability. Finally, the sensor can be connected directly with any type of microprocessor and microcontroller system through the I2C bus, thereby reducing the hardware cost of the interface circuit and simplifying the interface method. 3.1 Output features (1) Humidity value output SHT11 can directly output digital measurement humidity values through the I2C bus. The relative humidity digital output characteristic curve is shown in Figure 3. It can be seen from Figure 3 that the output characteristics of the SHT11 are certain non -linear. In order to compensate the non -linearity of the humidity sensor, the humidity value can be corrected according to the following formula: Rhlinear = C1 C2SORH C3SORH2 formula, SORH is the sensor's relative humidity measurement value, the coefficient value of the value As follows: 12 digits: SORH: C1 = -4, C2 = 0.0405, C3 = -2.8 × 10-68 bits: SORH: C1 = -4, C2 = 0.648, C3 = -7.2 × 10-4 (2) Temperature value output. Since the linearness of the SHT11 temperature sensor is very good, the following formula can be used to convert the temperature digital output to the actual temperature value: T = D1 D2SOT When the power supply voltage is 5V, and the resolution of the temperature sensor is 14 bits of 14 bits At this time, D1 = -40 D2 = 0.01, when the resolution of the temperature sensor is 12 bits, D1 = -40 D2 = 0.04. (3) The dew point value of the dew point calculation can be obtained according to the relative humidity and temperature value. The specific calculation formula is as follows: logew = (0.66077 7.5T / (237.3 t) [log10 (RH) -2] dp = [(0.66077 -Logew) × 237.3] / (logew -8.16077) 3.2 commands and interface timing SHT11 sensors have 5 user commands. Command sequence and command time order.
Table 1 SHT11 sensor command list command coding instructions
measurement temperature 00011 temperature measurement
measurement humidity 00101 humidity measurement n read register status 001111 " Read the "Status register
Write the status of the register 00110" Write "status register
Soft start 11110 restart chip, remove the error record of the status recorder 11 milliseconds, enter the next command
(1) Transmission starts starting starts starting starts starts. When initialized transmission, the "transmission start" command should be issued first. This command can change the DATA from a high level to a low level when the SCK is high, and the DATA is raised when the next SCK is high. Including three addresses (currently only supports "000") and 5 commands. When the ACK position of the data foot is at a low potential, it means that the SHT11 is correctly received by the command. , The following signal order will reset the serial port: that is, when the DATA cable is at high electricity, it triggers SCK more than 9 times (including 9 times). After that, a "transmission start" command should be issued.
Table 2 Table 2 SHT11状态寄存器类型及说明位类型说明缺省rn7 保留0 rn6 读工检限（低电压检查） X rn5 保留0 rn4 保留0 rn3 只用于Tests, you cannot use 0
2 read/write heating 0 levels
1 Reading/write do not download 0 download
0 read/write '1' = 8 -bit relative humidity, 12 -bit temperature Resolution. '0 '= 12 -bit relative humidity, 14 -bit humidity resolution 0 12 -bit relative humidity, 14 -bit humidity
(3) After the sequence of temperature and humidity measurement is issued, the control is issued The device has to wait until the measurement is complete. Use the resolution measurement of 8/12/14 bits requires about 11/55 / 210ms. To indicate that the measurement is completed, the SHT11 will make the data cable lower. At this time, the controller must restart the SCK. Then transmit two -byte measurement data and 1 byte CRC verification. The controller must confirm each byte by reducing the data to low, and all the amount Calculated from the right, MSB ranked first. The communication stopped after confirming the CRC data bit. If there is no CRC -8 verification, the controller will keep ACK stop communication after the measurement data LSB is measured. After the measurement and communication are completed, the SHT11 will automatically return to the sleep mode. It should be noted that the operating frequency of the SHT11 is lower than 0.1 ° C at this time cannot be greater than 15 % of the calibration value (such as 12 -bit accuracy, a maximum measurement of up to 3 times per second). The timing corresponding to the measurement temperature and humidity command is shown in Figure 4.
3.3 The register configuration of some of the advanced functions in the SHT11 sensor is achieved by a state register. The types and descriptions of the registers are listed in Table 2. The functional description of the register -related bit below: (1) After the heating is connected to the heating switch in the chip, the temperature of the sensor increases by about 5 ° C, which increases the power consumption to 8mA ＠ 5V. The heating purposes are as follows: ● By comparing the temperature and humidity before and after starting the heater, the functions of the sensor can be correctly distinguished; ● In the environment with a relatively high humidity, the sensor can avoid condensation by heating. (2) The low voltage detection SHT11 can detect whether the VDD voltage is less than 2.45V during work, and the accuracy is ± 0.1V. (3) Download the calibration coefficient In order to save energy and increase speed, OTP must be re -downloaded the calibration coefficient before each measurement, so that each measurement saves 8.2MS time. (4) Measurement resolution settings The measurement resolution will be reduced from 14 (temperature) and 12 -bit (humidity) to 12 and 8 bits, respectively in high -speed or low power consumption occasions.
4 Application Instructions 4.1 The temperature other than the measurement of the operating conditions will temporarily offset the humidity signal 3 %. Then the sensor will slowly return to the calibration conditions. If the chip is heated for 24 hours to 90 ° C under the environment of humidity less than 5 %, the chip will quickly restore the effects of high relative humidity and high temperature environment. However, extended strength conditions will accelerate the aging of the chip. 4.2 Installation Note Due to the close relationship between the relative humidity of the atmosphere and the temperature, the main point when measured the atmospheric temperature is to keep the sensor and the atmosphere of the same temperature. In order to reduce the thermal conductivity between SHT11 and PCB, the copper wire should be the finest and add a narrow seam to it. At the same time, the sensor should be avoided under strong light or UV. When the sensor is wiring, the SCK and Data signals are parallel and close to each other, or when the signal line is 10cm, the interference information will be generated. At this time, the VDD or GND should be placed between the two sets of signals.
5 Specific application Figure 5 is the interface circuit of AT89C2051 single -chip microcomputer and SHT11. Since AT89C2051 does not have the I2C bus interface, the universal I / O port of the single -chip microcomputer is used to virtual I2C bus, and the P1.0 is used to use the P1.1 port to the virtual clock line, and access on the data end. A 4.7kΩ pull -up resistance, at the same time, connects a 0.1 μF decoupled capacitor on the VDD and GND end. The C51 applications supported with the above hardware circuit are given below. ＃define DATA P1＿1＃define SCK P1＿0＃define ACK 1＃define noACK 0＃define MEASURE_TEMP 0x03 ／／测量温度命令＃define MEASURE_HUMI 0x05 ／／测量湿度命令／／读温湿度数据char s－measure(unsigned char ＊p- value, un-signed char ＊p_checksum, unsigned char mode){unsigned char error＝0;unsigned int i;s_(); ／／传输开始switch(mode){caseTEMP:error＋＝s_write_byte(measure_temp);break;caseHUMI: error = s_write_byte (meAsure_humi); break; default: break;} for (i = 0; i u003C65535; i ) if (data == 0) break; if (data) Reeor = 1; ACK);＊(p_value＋1)＝s_read_byte(ACK);＊p_checksum＝s_read_byte(noACK);return error;}／／温湿度值标度变换及温度补偿void calc_sth15(float ＊p_humidity,float ＊p_tempera-ture){ const float C1 = -4.0; const float C2 = 0.0405; const float C3 = -0.0000028; const float T1 = -0.01; const float T2 = 0.00008; float Rh = × P_Humidity; float; t = × p_; float rh_lin; float th_ture; float T_C; t_c = t × 0.01-40; rh_lin = c3 × rh × rh c2 × rh c1; TRH_TURE = (T_C -25) × (t1 t2 × rh) rh_lin; × p_ = t -c; × p_humidity = rh_ture;} // Calculate the dew point from the relative temperature and humidity charc_dewpoint (float H, Float T) {float logEx, DEW_POINT; logex = 0.6. 6077 7.5 × T / (237.3 T) [log10 (h) -2]; Dew_point = (logex -0.66077) × 237.3 / (0.66077 7.5 -logex); In length, the above program does not give the transmission start, writing line data, and reading byte data function.
6 SHT11 Digital temperature and humidity sensor is integrated into the sensor due to temperature sensor, humidity sensor, signal conditioning, mold / number converter, calibration parameter and I2C bus interface. Therefore, the sensor not only improves the sensor The performance also reduces costs and reduces volume, and is also very convenient to interface with microcontroller. It can be seen that the sensor is an ideal choice for the temperature and humidity testing of embedded systems.
I am the Chinese general generation of SHT. I can tell you responsibly that SHT10 and 11 except for precision except for accuracy, there is no difference. This is their complete exchanges!
This is very detailed, the link is as follows:
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