Datasheet

Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 2/7
Specification
Electrical specification:
Parameter min typ max Unit
Input Voltage 8 9 10 V
Input Voltage Ripple 0.5 V
External Supply
Supply Current 170 280 mA
Input Voltage 4.75 5 5.25 V
USB Supply
Supply Current 170 280 mA
Range 2.1 3.0 3.6 V
Resolution 0.1 V
Accuracy 2 5 %
Sensor Supply
Voltage
Output current 40 110
1
mA
Temperature Resolution 11 14 Bit
Humidity Resolution 8 12 Bit
Measurement interval 1 1440 s
Communication USB (via Virtual Com Port (VCP))
Operating
Temperature
0 – 50°C (multiplexer box)
-20 – 70°C (cables, sensor)
Default Configuration
Initial configuration set for the default mode (values can be
changed by using the measurement software)
Parameter Default value
Sensor Supply Voltage 3.0 V
Temperature Resolution 12 Bit
Humidity Resolution 12 Bit
Measurement interval 1 s
Heater off
SHT7x on
OTP reload
SHT2x off
Power Supply
Used Connection EK-H4 supplied from
DC DC (9V)
DC and USB DC (9V)
USB USB (5V)
The EK-H4 may be supplied by DC Power Supply Unit at
9V or USB connection at 5V. Power supply by USB is only
possible if USB driver is installed correctly.
Pin Name Comment
- GND Ground
+
Positive
Voltage
9V Supply
Table 1 DC Power Supply: Pin Diagram
1
short circuit current
EK-H4 Circuit Board
EK-H4 Pin Assignment
RJ45 Pin Sensor Pin Name Description
1 3 VSS Ground
3 1 SCL Serial clock
5 2 VDD Supply voltage
7 4 SDA Serial data
Table 2 Pin Assignments: Female RJ45 pin diagram on the
left – SHT21 and SHT71 sensors on the right of the upper panel.
LED Functions
LED Function
Power LED LED off denotes low supply
voltage (DC < 8V, USB < 4.75V)
or not connected.
Green LED Sensor detected RJ45
Connector
Orange LED Measurement is in progress
4 sensor channels
Display
2 buttons for
display modes
User field
connected to MCU
Micro Controller Unit
Debug interface
Reset button
USB interface
Power supply
Power LED
8 1
1 2 3 4
1
2
3
4
+