Hi Fabio,
I was a little busy so just reading all new posts for me. I finished a big project and I can tell you now that communications with Unistream is really a big advantage over Vision series. In the system I have:
12 slaves
Reading more than 800 coils
Writing more than 1,800 coils
Reading more than 160 Int16
Writing more than 70 int16
Reading more than 464 int32
Writing more than 360 int 32
each 1,000 ms the Unistream 15 is making the work perfectly.
The system is working 24 x 7 since December 2015.