Rockwell Automation 1756-RIO ControlLogix Remote I/O Communication Interface Module User Manual - Manual (Page 27)

Publication 1756-UM534B-EN-P - November 2010 27
The 1756-RIO Module-Getting Started Chapter 1
Enter the RPI
To set the RPI, follow these steps.
1. On the controller organizer, double-click on the RIO module.
2. On the Module Properties dialog box, from the Connection tab, set the
RPI for the module.
IMPORTANT
If you are using the 1756-RIO module in a remote rack, for
example, a rack connected to the controlling ControlLogix
controller over ControlNet or Ethernet/IP, it may be necessary to
increase the RPI, as the intermediate network may not have
sufficient bandwidth to support faster updates (small RPIs). The
likelihood of having bandwidth issues is increased as you
increase the number of 248-word input and output tags.