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User Manual May 2019 | Page 34/49
USER MANUAL
Scavenger Transmitter Module
STM 330 / STM 331 STM 331U / STM 332U / STM 333U
(Stepcode DE and later)
4.2
Temperature sensor
STM 33x provides an internal temperature sensor. The sensor is part of the EO3000I IC and
measures the chip temperature. Therefore it is important to provide a good thermal con-
nection of the IC to the environment by ensuring sufficient ventilation of air inside the
housing. Only then the measurement will represent the ambient temperature. Depending
on the design of the housing a delay between ambient temperature changes and measured
temperature value will be seen.
4.3
Set point control and occupancy button
In order to control the set point, an external potentiometer has to be connected as shown
below. In addition this figure shows how to connect the occupancy button.
4.4
Combination with humidity sensor module HSM 100
The humidity sensor module HSM 100 extends the functionality of STM 33x temperature
sensor modules. HSM 100 contains an internal calibrated humidity sensor. It can be
plugged onto STM 33x modules via the 20 pin connector. For details please refer to the
data sheet of HSM 100.
Heating of the chip due to its current consumption is negligible as the chip only
consumes 200 nA while in sleep mode.
Temperature measurement every second is not recommended as in this case ef-
fects of heating of the chip might become visible and accuracy is reduced.
STM 33x
HSM 100
STM 33x
S
W
P
W
R
G
N
D
A
D
IO
0
10k
O
C
C
U
V
DDe
x
t
Set Point
Occupancy
