Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 130)

130 Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Chapter 3 Digital I/O Operation
The table describes the two ways a module sends data to the owner-controller.
Set RPI
The Connection tab on the Module Properties dialog box lets you enter a
requested packet interval (RPI). The RPI guarantees the slowest rate at which
data is multicast to the owner-controller.
The module’s actual data transfer rate can be faster than the RPI setting. But, the
RPI provides a defined, maximum period of time when data is transferred to the
owner-controller.
Topic Description
Requested packet interval A user-defined rate at which the module updates the
information sent to its owner-controller. This is also
known as Cyclic Data Transfer.
Change of state Configurable feature that, when enabled, instructs the
module to update its owner-controller with new data
whenever a specified input point transitions from On to
Off and Off to On. The data is sent at the RPI rate when
there is no change of state. By default, this setting is
always enabled for input modules.
6