Sterlco A3 Blender Control and Data Acquisition Software - Manual (Page 117)

Page Number 117
Problem
You’ve configured more than one Ethernet device and some are
communicating, but others aren’t.
Solution
It is easy to trouble shoot when you have some devices communicating (at
least one). The quickest way to resolve the problem is first examine the
lights on the PLC and Ethernet module for a device that is working.
Compare this with one that isn’t working and then read the section on the
prior page. You can also simply swap cables and modules until you figure
out what is causing the problem and then focus on the problem.