mikroElektronika EasyPIC PRO v7, User Manual

Page: 31 / 41

The LM35 is a low-cost precision
integrated-circuit temperature sensor,
whose output voltage is linearly
proportional to the Celsius (Centigrade)
temperature. The LM35 thus has an
advantage over linear temperature
sensors calibrated in ° Kelvin, as the
user is not required to subtract a large
constant voltage from its output to
obtain convenient Centigrade scaling.
The LM35 does not require any external
calibration or trimming to provide
typical accuracies of ±¼°C at room
temperature and ±¾°C over a full -55
to +150°C temperature range. It has
a 10.0 mV/°C scale factor
and less than 60 μA current drain. As
it draws only 60 μA from its supply, it
has very low self-heating,
less than 0.1°C in still air.
EasyPIC PRO
™
v7 provides a
separate socket ( TS2 ) for the
LM35 sensor in TO-92 plastic
packaging. Readings are done
with microcontroller using single
analog input line, which is selected
with a
J4 jumper.
page 31
D
AT
A BUS
Figure 17-5: LM35 connected to RA3 pin
EasyPIC PRO
™
v7 enables you to get analog readings from the LM35 sensor
using RA3 or RF6 microcontroller pins. The selection of either of those two
lines is done using J4 jumper. When placing the sensor in the socket make sure
that half-circle on the board’s silkscreen markings matches the rounded part
of the LM35 sensor. If you accidently connect the sensor the other way, it can
be permanently damaged and you might need to replace it with another one.
During the readings of the sensor, make sure that no other device uses the
selected analog line, because it may interfere with the readings.
Figure 17-1:
LM35 not
connected Figure 17-2:
LM35 placed
in socket Figure 17-3:
LM35
connected
to RF6 pin Figure 17-4:
LM35
connected
to RA3 pin
Enabling LM35 Sensor
1 2 3 4
LM35 - Analog
Temperature Sensor
other modules
Easy PIC PRO
v7