From the RSLogix5, if you double click the “IO Channel”

Xybernetics Allen-Bradley RSLogix5 - IO Configuration Not Used Address

And let say for our example, we will double click the “Chassis 4” (in the I/O Configuration – Chassis table).
And after that, double click “Slot 11″ (in the Chassis Shassis_4, Rack6, Group 0” window.
This should bring you to the I/O card configuration screen. See screenshot below.

Xybernetics Allen-Bradley RSLogix5 - IO Configuration Not Used Address

If you lok at the “Data” column in the “1771-IFE at RGS 7/3/0” windows there are some yellow cells.
What does this yellow cell denote? It means that the PLC address has been assigned but not used any where in the PLC logic.
For example, if we try searching for address N9:351 in the PLC logic (Channel 8, “Fire Detection High” which has a yelow cell in Data column), you will get the address not found popup message.

Xybernetics Allen-Bradley RSLogix5 - IO Configuration Not Used Address

I hope it has helped.

n1849778
About the
I am a software developer in Calgary, Alberta, Canada with passion in getting my fingers in any new technology. I started software development when I was 10 years old and have never looked back. Now with well over 35 years of software development, I wanted to share some of these key knowledge with the people of the world in the wide web.