Rajnish,
The Automation List  managed by Control Technology Corporation
http://www.control.com may contain the information that you are looking for.

You might give the following PLC sites a try.
        www.plcdirect.com
        www.modicon.com
        www.ab.com
        www.ad.siemens.de
        www.ge.com
        www.omron.com
        www.control.com

Dave Gunderson
Hoover Dam Comm & Control Group

-----Original Message-----
From: Rajnish <challengers@TECHNOLOGIST.COM>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Friday, May 01, 1998 11:30 AM
Subject: [OT] Learning PLC's Ladder Logic


>Hi All,
>
>I want to learn about the PLCs Ladder Logic s'ware. I would appreciate if I
>could get some usefull links.
>
>Thanks,
>
>Rajnish.