SI7013 Datasheet, PDF (23/43 Pages) Silicon Laboratories – I2C HUMIDITY AND TWO-ZONE TEMPERATURE SENSOR

Si7013
5.1.1. Measuring Relative Humidity
Once a relative humidity measurement has been made, the results of the measurement may be converted to
percent relative humidity by using the following expression:
%RH = ¹----²---⁵---^--₆--^R-₅---^H-₅---₃-^_--₆-^C----^o----^d---^e-- – 6
Where:
%RH is the measured relative humidity value in %RH
RH Code is the 16-bit word returned by the Si7013
A humidity measurement will always return XXXXXX10 in the LSB field.
5.1.2. Measuring Temperature
Each time a relative humidity measurement is made a temperature measurement is also made for the purposes of
temperature compensation of the relative humidity measurement. If the temperature value is required, it can be
read using command 0xE0; this avoids having to perform a second temperature measurement. The measure
temperature commands 0xE3 and 0xF3 will perform a temperature measurement and return the measurement
value, command 0xE0 does not perform a measurement but returns the temperature value measured during the
relative humidity measurement.
Sequence to read temperature value from previous RH measurement
Slave
Slave
S
W
A
0xE0
A
Sr
R
A MS Byte A LS Byte NA P
Address
Address
The results of the temperature measurement may be converted to temperature in degrees Celsius (°C) using the
following expression:
Temperature (C  = -¹---⁷---⁵----^.-⁷----²---^-₆--^T--₅--^e-₅---^m3----₆-^p----^_---^C-----^o---^d---^e-- – 46.85
Where:
Temperature (°C) is the measured temperature value in °C
Temp_Code is the 16-bit word returned by the Si7013
A temperature measurement will always return XXXXXX00 in the LSB field.
Rev. 0.95
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