Just an update
I know this is an old post but I find that when I search for something half the time all I find is questions without answers or follow up by the poster. So here go's
Ken was correct in what he posted. I found that the first set of address was used for bit to and from the robot. These are things like start program, stop program, program running etc.. and general inputs and outputs that can be used for anything. The example I got from Yamaha only showed these bits being used. The example helped but did not do everything that I wanted. So I talked to another Yamaha guy and he sent me a manual on Devicenet. The Devicenet manual shows how to send commands and get status from the robot. The Profibus module that I am using uses the same commands as Devicenet. The commands use the second set of address in the hardware config. So currently I am working with the commands. From the looks of things it appears that you can do just about anything from Profibus that you can do from the robot program.
I am currently working on some function blocks for Step 7 that will do all the comms to the robots. I had high hopes that Yamaha would be able to hook me up with someone that had the blocks but I have not been that lucky. So if anyone now or in the future is trying to talk to a Yamaha Robot send me an email I might be able to help.