simple temperature control with Siemens controller

Hello to all.
I'm really bored these days and next week I'll get Siemens logo controller, and I was thinking to make a simple room temperature control using this controller. My main problem is electronics scheme I should use... Can you give me any suggestions...
Thanks

Ok guys, here's what I have in mind. I want to use Siemens logo to make a temperature regulation in room. Of course since this is just a toy project I decided to replace heater with a light bulb. I plan to use logo to give user an option to choose between two modes of working. First: temperature that turn on the light is 20 deg Cel, and temperature that turn off the light is 25 deg Cel. Second mode is ON = 25 and OFF = 30. I know I'll need some kind of thermocouple but I 'm not very familiar with it and want to learn. Can you give me any hints how to approach problem?
Thanks

Hello guys,
since there was no posting in this thread I assume I didn't ask
well specified question.
Here's what I'm dealing with:
I have one PT100 sensor which I intend to use as a temperature sensor.
I've downloaded Siemens logo!soft comfort demo program to see how can I use it.
I need to design a clasic on-off temperature controller (closed loop).
At first I thought to use voltage divider to convert signal from PT 100 into
a voltage signal between 0 to 10 V.
I plan to use logo as regulator: if temperature drop 25 deg Celsius out from controller is
voltage signal that can trigger a heater. If temperature is above 30 deg controller gives signal (0)
to turn off heater.
I plan to use one analog inut, and to use constant value as setpoint. These two signals I plan to connect
to analog comparator where I can set on and off. Output from comparator is connceted to digital
output that can be 0 or output voltage (I'm not sure what output voltage logo gives)
However in properties of analog comparator I can chose Sensor: PT100, so exactly what I want.
If I choose PT100, I'm not sure how logo will interpret this.
If I choose PT100, will that mean that logo expects both input signals to comparator are
from PT100 or not?
Also how to to represent constant value in Siemens logosoft program?
Thanks for help