Hi Harshada,
I do not intend to dishearten you, but implementing a successful PID algorithm takes a lot of testing, observation and studying.
Bottom line: It takes a lot of time to complete this product.

First: You have to study the system. Re-read the points mentioned by Micheal Karas. It is a lot complicated than you think. If there is any other task such as getting data from PC, sending over ethernet,etc,etc...you can reach a final answer; but in PID control, there is no final answer.

Here you have to identify where is the problem, in the PID algorithm, in the values of P, I, D, the Dead time, the Cycle time of the output, etc. or in the system.

I have downloaded over 27MB of files from the net, just to study the PID Logic and tuning methods. It took me almost about 3 months to complete a successful PID Controller after studying it for nearly 4 months. God knows, how many times I slept on those notes....it makes me feel drowsy even to think about it. But once you see the great white light, it will be crystal clear to implement the PID algorithm.

Just google "PID algorithm and you find hundreds of websites with source codes. You have search and study them.

So if you are looking for a quick fix solution, then let me tell you, it is not that simple.

You have not mentioned your email ID in your profile. I could send some of them to you.

And one more thing:
When you want to post a source code in this forum use the "Insert Program Code" button.

"code=filename.txt]...insert code here/code"

And copy-paste your code at the location "Insert Code Here".