Addressing PLC-5 16-Slot Chassis as Remote I/O from ControlLogix

We have a PLC-5 with 16 I/O Modules in a single chassis. 1-Slot addressing is used with a 8) 16pt-Input and 8) 16pt-Output modules.

The I/O modules are in a scattered arrangement .
e.g. IIIIIIOOOOOIIOOO

We are replacing the PLC-5 processor with a 1771-ASB Remote I/O scanner and addressing the rack from a ControlLogix processor with a 1756-DHRIO module.

Since the Remote I/O scanner only has 8) 16-bit Input and 8) 16-bit Output data words available how will it map the remote modules to the data?
Will it automatically consolidate all the input modules together into Rack_1:I: Data[0-7] and the output modules into Rack_1:O: Data[0-7]? What would happen if there were 9 Input modules and 8 Output modules?

From Chpt 8 of the DHRIO manual

The 1756-DHRIO module scans the remote I/O devices as they appear in the ControlLogix controller’s controller organizer. The entries in the organizer represent logical adapters. The physical adapter modules on remote I/O may act as several racks. This depends on the addressing mode of the physical adapter and chassis.

Add a new entry in the I/O Config for the second logical rack

OG

I talked with Rockwell and they verified that a rack with 16-Modules and 1-Slot addressing will appear as 2 separate racks to the Remote I/O scanner.

e.g. If the rack is addresses as Rack #1 the scanner will see Rack #1 and Rack#2 each with 8 Modules.

Yes, but you still have to add the entry to the I/O Config for both racks. That is what creates the tags you will need.

OG

I can confirm (having done this exact scenario many times) that Operaghost is 100% correct.

Basics : your 16-slot physical chassis can be configured to be 1, 2, or even 4 logical racks, depending on the addressing mode set by the chassis switches.

1 rack if 2-slot addressing
2 racks if 1-slot addressing
4 racks if 1/2-slot addressing

What you must do in Logix5000 is to add an entry for each and every logical rack.

As stated, that is the only way you will get the tags in the Logix5000 database to "communicate" with your I/O devices.