matlab black box system identification

Dear All,

I have a problem and tring to find a solution by using matlab system identification model but dont know how.Firstly want to explain problem;

There is a system and the input range between 0..255 and also the output range is 0..255. But the output changes the same input according to temperature. I mean It0=10 Ot0=15,It1=10 Ot0=15 .... I am tring to identify this system any math function and by using this fucntion with some values test it and get the output values.

How can i do it? Is there any simple example that shows finding system math output function ralted to inputs and using it for test.

Best regards,

Metin