Dear Nikhorn, Peer is out of office at present, so I will reply since it is urgent.
The new Master-Hub should be placed at a convenient place for connecting the cables from the Sub-Hubs at silo 3 to silo 6 and the moisture sensor Sub-Hub ID 01 and for connecting AC Mains to the new Master-Hub. It could be as indicated on the photo or somewhere on the cat-walk between silo 3 and silo 6.
The cable length between the two Master-Hubs is not critical whereas the cable length between the sensor cables and the Sub-Hubs, between the Sub-Hubs and between the Sub-Hubs and the Master-Hub should be kept as short as possible.
I do hope this will do.
Best regards,
Knud Erik