Why Yet Another Fieldbus?

Thats a good question.
Another question is, why do all existsing Filedbus implementation turn to Ethernet?
Could it be because the populatiry of the internet protocols?
Could it be because it seems to be so easy to get devices to cooperate in an office enviroment? Just hook up your printer o scanner o camera to the network and it pops up as an icon in your PC.

Then here's another question: Why didn't the implementors of the existing fieldbus protocols try to extend the existing internet protocols, and reuse what already exists?

That's what PieP do. Piep uses TCP/IP to create a fieldbus protocol in the most simple way, just like all other internet protocols like FTP, SMTP,...