28018 Parallax Inc, 28018 Datasheet - Page 2

• Manufacturer Part Number: 28018
• Description: MODULE SENSOR TEMP+HUMIDITY
• Manufacturer: Parallax Inc
• Series: Sensirion SHT11r

Specifications of 28018

• Output Type: Digital - 2-Wire
• Sensor Type: Humidity and Temperature
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

SHT1x / SHT7x Relative Humidity & Temperature Sensor System
Parameter
Humidity
Resolution
Repeatability
Accuracy
Uncertainty
Interchangeability
Nonlinearity
Range
Response time
Hysteresis
Long term stability Typical
Temperature
Resolution
Repeatability
Accuracy
Range
Response Time
Table 1
2
Figure 2
2.1 Power Pins
The SHTxx requires a voltage supply between 2.4V and
5.5V. After powerup the device needs 11ms to reach its
“sleep” state. No commands should be sent before that time.
Power supply pins (VDD, GND) may be decoupled with a
100 nF capacitor.
2.2 Serial Interface (Bidirectional 2-wire)
The serial interface of the SHTxx is optimized for sensor
readout and power consumption and is not compatible with
I
(1)
(2)
www.sensirion.com
1 Sensor Performance Specifications
2
C interfaces, see FAQ for details.
Each SHTxx is tested to be within RH accuracy specifications at 25°C (77°F) and 48°C (118.4°F)
The default measurement resolution of 14bit (temperature) and 12bit (humidity) can be reduced to 12 and 8 bit through the status register.
(master)
uC
Interface Specifications
(1)
Sensor Performance Specifications
Typical application circuit
(2)
(2)
Vdd
Conditions Min. Typ. Max. Units
1/e (63%)
slowly moving air
1/e (63%)
DATA
SCK
Vdd 2.4 - 5.5V
linearized
linearized
raw data
GND
0.04 0.01 0.01 °C
0.07 0.02 0.02 °F
0.5 0.03 0.03 % RH
-40
-40
12
8
0
5
Fully interchangeable
see figure 1
see figure 1
±0.1
±0.1
±0.2
<<1
< 1
±3
±1
12
14
4
SHT 1x
(slave)
123.8 °C
254.9 °F
100 % RH
12 bit
14 bit
30 s
% RH
% RH
% RH
s
% RH
% RH/yr
°C
°F
v2.0 March 2003
2.2.1
The SCK is used to synchronize the communication between
a microcontroller and the SHT1x / SHT7x. Since the
interface consists of fully static logic there is no minimum
SCK frequency.
2.2.2
The DATA tristate pin is used to transfer data in and out of
the device. DATA changes after the falling edge and is
valid on the rising edge of the serial clock SCK. During
communication the DATA line must remain stable while SCK
is high. To avoid signal contention the microcontroller should
only drive DATA low. An external pull-up resistor (e.g 10kΩ )
is required to pull the signal high. (See Figure 2) Pull-up
resistors are often included in I/O circuits of microcontrollers.
See Table 5 for detailed IO characteristics.
± 3°C
± 2°C
± 1°C
Figure 1
± 4°C
± 3°C
± 2°C
± 1°C
± 0°C
± 5°C
± 5%
± 4%
± 3%
± 2%
± 1%
± 0%
0°C
-40°C
-40°F
0%
0%
Serial clock input (SCK)
Serial data (DATA)
Rel. Humidity, Temperature and Dewpoint accuracies
10%
10%
SHT15/75
20%
20%
32°F
0°C
30% 40%
30% 40%
SHT15/75
SHT11/71
SHT11/71
SHT11/71
104°F
50%
40°C
50%
60%
60%
SHT15/75
70%
70%
176°F
80°C
80%
80%
90 %
90 %
100%
120°C
248°F
100%
± 5.4°F
± 3.6°F
± 1.8°F
± 9.0°F
± 7.2°F
± 5.4°F
± 3.6°F
± 1.8°F
%RH
%RH
0°F
2/9