Bespoke Ethernet Communications to Controllogix 5550 over Ethernet


Thread Starter

Mark Grimsey

A current project requires communications from our Linux application to a number of Modicon and Allen Bradley PLC's. The Modicon comms. is easy and works fine but we are struggling to get the packet structure right for the Allen Bradley PLC. Is there anyone out there who has done something similar that can point us in the right direction?

We are trying to encapsulate CIP messages to read a single data point within an Ethernet/IP packet as a test to start with.

We can happily register and de-register from the device at the Ethernet/IP level but our CIP packet structure returns an error.


Download my CELL (CIP/Ethernet Library for Linux) library -

This library will allow you to read and write any tag within a ControlLogix - and it works! :)

Ron Gage