RPI (requested packet interval)
The rate, set per connection, at which an EtherNet/IP controller and a device exchange cyclic I/O data.
The network analogy
A fixed transmit interval for a UDP stream that doubles as a heartbeat. Every interval carries the latest values, and enough silence means the connection is declared dead.
Why it matters for wireless
The connection timeout is a multiple of the RPI, so the RPI and its multiplier together set the longest gap a roam or retry burst can create before the device faults. A shorter RPI also puts more packets per second on the air.
EtherNet/IP inputs are not polled. A device produces its data on a change of state or at the RPI, and the controller consumes it over UDP. One vendor’s manual states that an implicit connection times out in controller multiplier x RPI, with the multiplier chosen so the timeout is at least 100 ms and never below 41. Its examples: a 2 ms RPI with a multiplier of 64 gives 128 ms, and a 10 ms RPI with a multiplier of 16 gives 160 ms. That is one vendor’s rule, so confirm the multiplier your controller actually uses.
Safety connections apply the same idea with tighter limits. Their connection reaction time limit is also computed from the RPI, which is why the RPI is the first number to ask for when control traffic goes wireless.
About this page
Built from 3 sources: 3 vendor documents. Researched and drafted with AI assistance, then reviewed and approved by Ben Rutter on . How pages are made
- First published
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Cite this page
Plain
Ben Rutter. "RPI (requested packet interval)." OT Wireless, published October 5, 2026. https://otwireless.com/glossary/rpi/
APA 7
Rutter, B. (2026, October 5). RPI (requested packet interval). OT Wireless. https://otwireless.com/glossary/rpi/
BibTeX
@misc{rutter2026rpi,
author = {Rutter, Ben},
title = {{RPI (requested packet interval)}},
year = {2026},
howpublished = {\url{https://otwireless.com/glossary/rpi/}},
organization = {OT Wireless},
}