ProSoft Technology CLX-APACS - Manual (Page 19)

QTS-CLX-APACS Page 13
For example, you can use a longer RPI for the diagnostic data in connection 9, for
example 500 milliseconds, since diagnostics do not need to be updated as frequently as
I/O data.
Remote Connections
If you are using the QTS-CLX-APACS in a remote chassis, for example a chassis
connected to the controlling ControlLogix processor over Ethernet or ControlNet, it may
be necessary to increase the RPI, as the intermediate network may not have sufficient
bandwidth to support faster updates (small RPIs).