Download and trial the EtherNet/IP Function Blocks to communicate with Rockwell ControlLogix PLC's. A 72 hour demonstration mode is supported by the S7-300 CP Co-ordinator Function Block. The demonstration mode can be restarted when it expires by restarting the S7-300 CPU.
Develop your communication strategy and fully test in the demonstration mode. Purchase your runtime licence when you are satisfied with the solution.
This is a software solution which utilises the existing Ethernet capabilities of the PLC systems you wish to connect. No hardware gateway is required.
The Manual and instruction videos provide the guidance to easy connect a Siemens S7-300 PLC with a Communications Processor to a ControlLogix PLC using EtherNet/IP.