Hi russg,
what PLCs/Devicenet cards do you have?
Generally you need RSNetworx for Devicenet to upload the configuration, if you do not already have a file. Latest version I have is 21.
If you are working on ControlLogix or CompactLogix, these details can be gathered through the Hardware configuration, by right-clicking on the Devicenet card, properties, and RSNetworx and gathering the network information and saving to a .dnt file.
If you are on PLC5 and have a 1771-SDN scanner, then you will need a Devicenet cable (USB to Devicenet) and attach your cable as a piggyback to the network connections on the scanner - they used to do a piggyback cable for these, but they are obsolete, although I picked one up a couple of years ago and it does make the job easier.