Input and Output Sizes (1771-ACN15 and 1771-ACNR15)

At module creation time in the

Logix Designer

application, you are required to provide an Input and Output Size. This setting takes the number of slots in your chassis and the slot addressing mode you are using into consideration. Addressing modes are set via DIP switches on the chassis, and can be 2-slot, 1-slot, or 1/2-slot. Each slot, beginning with slot 0 in a 1-slot addressing mode setting, is assigned one input word and/or one output word (16 bits, one I/O group).

An I/O group is a group of inputs and/or outputs that correspond to one word each in the input and/or output image tables.

Use the table as a guide to understanding chassis size, slot addressing modes, and setting Input and Output Sizes in the RSLogix software.

An example of 1-slot addressing mode in relation to setting Input and Output Sizes in the

Logix Designer

application is provided below.

For an 8-slot chassis using 1-slot addressing, there are 8 16-bit input and/or output words of data produced and/or consumed. Therefore, if you have a 4-slot chassis set to 1-slot addressing then you may specify an Input and/or Output Size between 1 and 4 depending on the physical location of the input and output modules.