can you tell me which of the latest systems support the S400 I/O modules on the masterbus network please
The AC450 or the AC110 can support these. But it's older technology and the masterfieldbus is not in the active lifcyle any more.
There are conversion kits availlable which have the same outline and connectors as the S400 IO and use S800 modules. But there is a litle catch with these as they sometimes have less IO channels as the S400IO. See document 3BSE037624 about the conversion kit.
The S400 series I/O is now obsolete. It was only supported on MP200 and AC400 series controllers. There are no options to move it to another controller. If you are upgrading your AC400 or MP200 controller you will need to replace the I/O modules and bus as well.
There is an upgrade kit available for replacing the I/O modules with S800 I/O and AF100 on an AC400 series controller.