Rockwell Automation 1756-RIO ControlLogix Remote I/O Communication Interface Module User Manual - Manual (Page 29)

Publication 1756-UM534B-EN-P - November 2010 29
The 1756-RIO Module-Getting Started Chapter 1
Throughput
When using the 1756-RIO module, your system throughput is based on the
following key factors:
 Number and sizes of adapters
 Number and sizes of block transfer modules
 Overall remote I/O update time
 RPI
 Any network cards involved
 Controller scan time
 The asynchronous nature of the RPI and the remote I/O scan
Since the RIO scan is asynchronous to the RPI, the worst case, or maximum
update time to get information from the 1756-RIO into the controller is the
RPI plus two times the remote I/O update rate.
You can use the diagnostic functions of the 1756-RIO configuration tool’s
utilities to measure the average, minimum, and maximum update times on the
Remote I/O network.