Welcome to the forum.
A little more information will be helpful.
1) What brand and model PLC are you using?
2) What means of communicating with it (Ethernet, serial, Modbus, etc) do you have?
3) What data do you want to gather and how much of it do you want?
The more information you can provide the better we can help you reach a solution you will be happy with.
You probably don't want to log dirctly to Excel because of its data limitations but Excel can open a number of databases.