My experience is pretty much limited to direct serial comms with Toshiba and Siemens PLCs (seperately, of course), but I suspect the generalities cross over to others:
The Allen Bradley Micro830 PLC you intend to use allows configuration of the RS232 port to ASCII. This would allow you simply query the PLC for data, assuming you can put together a query string that the PLC will respond to (same goes for command strings). The cable needed might be as simple as gnd/tx/rx or it could also require a control line (RTS, CTS, etc.).
I started out by using a terminal emulator (on a old Epson POS), simply trying to get a relay to latch. Once I got that (which told me I had the packet properly configured) I was on my way.
That done, you could then program the PC to display that data captured however you wish. Or go further and develop a full blown GUI "control panel".
This may be somewhat dated advice.