In one of my project, Iam using SLC5/04 with BSN in 4 slot rack. Similar rack is also there for secondary system. In RIO rack there are 10 Nos of IB 16 and 7 nos of OB16 and 1 no of NI16I (16 channel analog input module). Here iam using 1 slot addressing in ASB. My question is how to write coding in BTR and BTW for reading data from analog input module 1746-NI16I. Is there any special considerations to be considered for this?? I have searched all the catalogs, but couldnt get the required information. Can anybody give me the solution for this..

Rockwell Automation offers a far superior redundancy system in the ControlLogix platform.

All the information you need is available online from Rockwell Automation in two locations: The Literature Website and the Knowledgebase.

Start with the User Manuals for the RIO Scanner, the RIO Backup Scanner, and the RIO Adapter.
1747-UM013 1747-SN User Manual
1747-UM010 1747-BSN User manual[url="http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um006_-en-p.pdf"]
1747-UM006[/url] 1747-ASB User Manual

If you are not familiar with Block Transfer instructions (BTR and BTW), read about those in the big SLC-500 Instruction Set Reference Manual:
1747-RM001 SLC-500 Instruction Set Reference, revised November 2008

You will need User Manuals for the 1746-NI16I
1746-UM001 1746-NI16I, NI16V User Manual

And finally, read in the Knowledgebase about the 1747-BSN (especially the 2007 Safety Notice), about 1746-NI16I modules, and about remote chassis 1747-BAS or other "smart" modules.

Answer ID# 40824, Service Advisory - SLC 500 Backup Scanner faults during switchover when BTW and BTR are used.

Answer ID # 18488, Using the BTR/BTW to Block Transfer to a remote 1746-BAS

Answer ID # 19378, 1747-BSN Frequently Asked Questions

Answer ID # 18220, 1747-BSN Backing up Remote I/O and DH+ with Multiple 1747-BSN

There are several other Knowledgebase articles regarding the equipment you are using; use 1747-BSN as your keyword to find them all.