Actually i wanted to learn digital control systems.. i have been surfing for good tutorial in the internet but i couldnt find any good one.. can u please tell me where i can find a better one?
Try this Parallax.com downloads page:
**broken link removed**
Look for "What's a Microcontroller?" and download it, then read it. When done, download "process Control" and/or "Industrial Control" and read them. Pretty safe to say by the time you get done you should have a good background on the subject(s). These are sizable, so I hope you have fast internet or a lot of patience.
There are many examples of that kind of system. Most will probably use a uC or some other programmable device. I would start with some kind of uC projects. The Parallax would be good, but is more expensive and limited than learning how to program and interface uC's by themselves.