Siemens drives : direct data exchange

Has anyone experience with 'direct data exchange' on Siemens drives which are on profibus? This configuration is used for communication between drives on the same profibus whithout passing the data to the master (data is broadcasted). I would like to use this on Sinamics G120 drives for speed synchronisation. The drives are on the profibus that also goes to the field io. The bus speed is 1.5M.
What can I expect for the communication speed? Will this be as fast as coupling the drives with analog inputs and outputs to eachother?
What about the extra busload?

Thanks

Slave to slave communication

Is there realy anyone who has experience with slave tot slave communication (also called internode communication or direct data exchange). Preferebly with drive, but it is also possibly between plc's. I have troubles setting up the configuration.
Please reply if you have experiences.
Thanks

Havent tried it myself, but a quick search on Siemens support immediately reveals http://support.automation.siemens.com/WW/view/en/22421343 for drive-to-drive comms. Have you seen that already ?

For knowing how fast the data exchange is, if you have setup the configuration including the drive-to-drive part, you can investigate the Profibus Bus Parameters. TTrtyp is the "typical" token rotation time which is exactly what the name says. Without knowing too much about slave-to-slave comms, I would guess that all data is exchanged within that Token rotation time.

Siemens drives : slave to slave communication

Thanks for your quick reply. But I already based my tests on that case in the Siemens Support. I only have G120 drives so I cannot check the configuration in the example with MM4. But if I try something comparable with Sinamics G120 I always get a busfault on the drive configured for direct data exchange.
The supporline of Siemens could not help me so far, so I hoped someone had already used it before.
Thanks