Thank you very much raghu for your reply and that good link to PID tutorial. It is certainly very helpful. I tried searching for simulator on google but can't find it. I am getting hundreds of links to hot pepper sauces but not the simulator. Please mail the simulator. Please don't mail at prahladpurohit@hotmail.com as I can't recieve big attachments on hotmail ID. I have sent you a mail with the e-mail ID please send me on that ID.

Regards,
Prahlad Purohit