@Tim Wescott just ported to his blog his famous 'PID without a PhD' article.
Also, please feel free to offer Tim a beer (beer button at the top of his article) to reward him for his efforts. Don't forget that the 'beer' ($2) won't be paid by you but through the reward money raised with the Vendors Directory.
Finally, please use this thread to discuss the article and share your experience and insights working with PID controllers.
This looks very good. Thanks!
I also recommend this book: http://www.amazon.com/Feedback-Control-Computer-Sy...
That was a great read! Thanks - it has demystified much of PID control for me.