Heater model in Simulink

Hi.

I'm student and I have a "little"problem. I need to build object model in Simulink. It's metal cube with three heaters (Sinkoplex, 350 W, 230 V) and a thermocouple. Heaters are turning by contactor. To controling this object I must use P, PI and PID controller i I must watch how they work (control signal 0 or 230 V and mV signal from thermocouple).

How can I build this model? Is there anybody, who could help me?

Thanks for help and sorry for my english ;)

Aron