First asking the question for a second time wont get you help any faster. second post : viewtopic.php?f=29&t=204969&p=1271002#p1271002
Without knowing what connection/data transfer protocols the PLC supports how can anyone say, you will need to figure out what your particular PLC is programmed to do with regards communications.
Visualization of data is down to what data you have and how you want to display it , do you want just rows of readings or graphs of data over time or some combination etc..... is it to be just a screen connected to the pi or some thing you need to access remotely ?
you will need to write your own program to collect the data from you r PLC and display it the format you want the programming language you use will depend on what you know and what supports the PLC data stream.
I suggest you start doing some research you have the whole web at your finger tips don't expect other people to do this research for you.