Electronic Components Datasheet Search
Selected language     English  β–Ό


1-100707-01 Datasheet(PDF) 8 Page - Sensitron

Part No. 1-100707-01
Description  Humidity and Temperature Sensor
Download  12 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  SENSITRON [Sensitron]
Homepage  http://www.sensitron.com
Logo 

 
 8 page
background image
Datasheet SHT21
www.sensirion.com
Version 1.0 – January 2010
8/12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
S 1 0 0 0 0 0 0 0
1 1 1 1 0 1 0 1
I2C address + write
Command (see Table 6)
19
20
21
22
23
24
25
26
27
Measurement
S 1 0 0 0 0 0 0 1
measuring
I2C address + read
19
20
21
22
23
24
25
26
27
Measurement
S 1 0 0 0 0 0 0 1
continue measuring
I2C address + read
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
0 1 1 0 0 0 1 1
0 1 0 1 0 0 1 0
Data (MSB)
Data (LSB) Stat.
46
47
48
49
50
51
52
53
54
0 1 1 0 0 0 1 1
P
Checksum
Figure 14 No Hold master communication sequence – grey
blocks are controlled by SHT2x. If measurement is not
completed upon β€œread” command, sensor does not provide ACK
on bit 27 (more of these iterations are possible). If bit 45 is
changed to NACK followed by Stop condition (P) checksum
transmission is omitted.
In the examples given in Figure 13 and Figure 14 the
sensor output is SRH = β€˜0110’0011’0101’0000’. For the
calculation of physical values Status Bits must be set to β€˜0’
– see Chapter 6.
The maximum duration for measurements depends on the
type of measurement and resolution chosen – values are
displayed in Table 7. Maximum values shall be chosen for
the communication planning of the MCU.
Resolution
RH typ
RH max
T typ
T max
Units
14 bit
66
85
ms
13 bit
33
43
ms
12 Bit
22
29
17
22
ms
11 bit
12
15
9
11
ms
10 bit
7
9
ms
8 bit
3
4
ms
Table 7 Measurement times for RH and T measurements at
different resolutions. Typical values are recommended for
calculating energy consumption while maximum values shall be
applied for calculating waiting times in communication.
Please note: I2C communication allows for repeated Start
conditions (S) without closing prior sequence with Stop
condition (P) – compare Figures 13, 14 and 16. Still, any
sequence with adjacent Start condition may alternatively
be closed with a Stop condition.
5.5
Soft Reset
This command (see Table 6) is used for rebooting the
sensor system without switching the power off and on
again. Upon reception of this command, the sensor
system reinitializes and starts operation according to the
default settings. The soft reset takes less than 15 ms.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
S 1 0 0 0 0 0 0 0
1 1 1 1 1 1 1 0
P
I2C address + write
Soft Reset
Figure 15 Soft Reset – grey blocks are controlled by SHT2x.
5.6
User Register
The content of user register is described in Table 8.
Please note that reserved bits must not be changed.
Bit
# Bits
Description / Coding
Default
7, 0
2
Measurement resolution
RH
T
β€˜00’
12 bit
14 bit
β€˜01’
8 bit
12 bit
β€˜10’
10 bit
13 bit
β€˜11’
11 bit
11 bit
β€˜00’
6
1
Status: End of battery16
β€˜0’: VDD > 2.25 V
β€˜1’: VDD < 2.25 V
β€˜0’
3, 4, 5
3
Reserved
2
1
Enable on-chip heater
β€˜0’
1
1
Disable OTP reload
β€˜1’
Table 8 User Register. Cut-off value for End of Battery signal
may vary by Β±0.05V. Reserved bits must not be changed. β€œOTP
reload” = β€˜0’ loads default settings after each time a
measurement command is issued.
The End of Battery alert is activated when the battery
power falls below 2.25V.
The heater is intended to be used for functionality
diagnosis
–
relative
humidity
drops
upon
rising
temperature. The heater consumes about 5.5mW and
provides a temperature increase of about 0.5 – 1.5Β°C.
OTP Reload is a safety feature and loads the entire OTP
settings to the register before every measurement. This
feature is disabled per default and is not recommended for
use. Please use Soft Reset instead – it contains OTP
Reload.
An example for I2C communication reading and writing the
User Register is given in Figure 16. It is important that first
the content of the register is read in order getting the
default values. Hereafter, the resolution is changed by
configuring register. Please note that the reserved user-
register bits must not be changed.
16 This status bit is updated after each measurement




Html Pages

1  2  3  4  5  6  7  8  9  10  11  12 


Datasheet Download




Link URL

Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights ReservedΒ© Alldatasheet.com 2003 - 2017    


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl