Hello  sam;

You could start by looking at the following Application Notes, both of the document links have sections on setting up redundant IM 153-2s:

Configuration of Redundant I/O Modules in SIMATIC PCS 7

I have taken the liberty of preparing a printout of the setup procedure as an attachment.

One important point: you have planned on using active bus modules (and the special rail for these) to build your redundant Et 200M stations, I hope.

If not, please look at section 1.3 in the links of the Application note, this is critical.

You will find some descriptions and links to part numbers for active bus modules for a redundant IM 153-2 in the following discussion:

simatic s7400 H with io modules 400 redundant 

Hope this helps,

Daniel Chartier