I am a novice to ladder programming. Does someone have the resource of introduction to the programming method and example program? Thanks a lot for you kindness.
Check out this site: http://www.plcs.net and go to the online tutorial. I am a novice too and it helped greatly. It has a full on-line tutorial to ladder programming and includes animations and links.
Regarding your problem I can refer you also to this web site "http://www.tri-plc.com":http://www.tri-plc.com and you can explore the ladder programming as you wanted.
I learn a lot from this web site.