I need some basic help with PLCs (HW vs SW PLC, vizualization libs)

Hello,
I'm new to PLC's. I'm working on a project for my school. At 1st step I'm supposed to gather some basic information, but I don't exactly know where to look for them. I need to compare hardware and software PLCs, note their advantages and disadvantages. Then I'm supposed to find some vizualization libraries for PLCs and compare their functionality, what they allow programmers to do, how they work and so on. Does anybody have any suggestions? I would be thankful for any information (a few lines of text or some links). Thanks in advance.

Roman

Start with this site here has good tutorial. Then get the book offered here. These are not the answer to your question I know but I think you need to know the basics (ie nuts and bolts?) of PLCs before getting into those "more advanced? topics.

Dan Bentler

Well, I've already studied a little. The problem is I need to write several pages long document in 10 days. Then I get a few more months to study and finish my project .. Sooo maybe it would be great if you could note some main, principal differences (or pros and cons) between hardware and software PLCs. Thanks .

Roman

This may help

http://www.plctalk.net/qanda/showthread.php?t=18189&highlight=soft+PLC

Thanks a lot! This linked thread seems to be right for me. There are quite a lot of pros and cons written there... Now I need to find some visualization libraries for any PLCs so I get to know what functions and use they have. Well I have a clue, I have some ideas, I would just like to get some of them so I can see how they are used, how they work .

Try here
http://www.htservices.com/Tools/OperatorInterfaces/

Thanks, this one seems to be good too and there are lots of links, hopefully some good ones ).