Datasheet

Datasheet Evaluation Kit EK-H5
www.sensirion.com July 2015 – Version 3 2/5
EK-H5 Pin Assignment
Sensor Pin
Name
Description
1
SCL
Serial clock
2
VDD
Supply voltage
3
VSS
Ground
4
SDA
Serial data
Table 1 Pin Assignments: SHTxx on PCB, SHT71 and
SHTxx on FPCB sensors.
Viewer Software
The appearance of the viewer software is slightly different
for the different sensor types. The main difference is that
the viewer software for the SHT3x includes additional
features (Alert mode, Heater and ART), which are not
available in the other sensor types.
The viewer software displays relative humidity and
temperature data on two different windows. It allows for
setting absolute or relative timing and change the
displaying between °C and °F. The data may be logged,
stored and exported to a CSV file, which can be imported
to Microsoft Excel.
Figure 3 Viewer Software window for the SHT3x
The viewer Software must be downloaded from the
Sensirion web page:
http://www.sensirion.com/usb-viewer/
Please note that the USB stick, sensor cable and sensor
must be connected to the computer before starting the
software. No further software driver or any other hardware
is required for running EK-H5.
When starting the viewer software, the type of sensor must
be selected in a first window (several sensors are given for
choice). The settings (explained below) must be chosen
and then the measurement may be started.
Features
Sampling Time [s]: Defines the number of measurements
per second. For the SHT2x, SHT1x/SHT7x and SHTC1
sensor series the measurement intervals are free of choice
in the range from 1 … 1440s.
The SHT3x is operated in periodic-mode: the value in this
field is rounded to the nearest periodic acquisition
frequency as shown in the datasheet. After clicking the
RUN button a single initial command is send to the sensor.
After this the viewer software only reads out the measured
values from the sensor. When the STOP button is clicked,
the sensor stops to measure and is switched to idle mode.
Resolution: Allows changing the resolution for SHT2x and
SHT1x/SHT7x for RH & T. The sensor SHTC1 and SHT3x
always measure with the highest repeatability (longest
measurement time).
Heater: This checkbox is only available for the SHT3x
series and switches the built-in heater on/off (ticked/not-
ticked). Since the heater power is dependent on the supply
voltage, higher temperatures are achievable with larger
V
DD
, and vice versa. Please note the supply voltage of the
EK-H5 cannot be changed, it is fixed to 3.3 V.
ART ON: The SHT3x’s unique Accelerated Response
Time (ART) functionality is controlled through this box.
This feature electronically speeds up the humidity
response of the sensor. This feature only works in periodic
mode at 4 Hz and for high-resolution measurements. For
this reason the sampling time is set to a predefined value
of 0.1 s. Changing the sampling time in this mode only
affects the time when the viewer reads out values from the
sensor, but it does not affect the acquisition frequency of
the sensor itself.
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