Look Here

I have never used one of these, have no idea what they cost, just saw it in a news letter. But would this work in place of an Net-ENI for connecting a MicroLogix 1200 to an Ethernet I/P network?

There are a handful of TCP/IP Ethernet to RS232 serial interfaces like that one on the market. I prefer the LanTronix "CoBox" and the Digi One, but there are literally dozens that work in the same way.

What they don't do is convert between DF1 and EtherNet/IP, which the 1761-NET-ENI does.

With a generic "Ethernet Serial Server" you can tunnel a serial protocol like DF1 across an Ethernet network with two Serial Servers. Or you can connect a computer with a serial driver to a "virtual COM port" and have the data redirected to the serial port of the Serial Server over Ethernet.

If all you need to do is connect visualization, datalogging, or programming software to the controller, generic serial servers are a good choice.

If you need to have A-B controllers on EtherNet/IP communicate with A-B controllers on RS232, you need the 1761-NET-ENI.

Thanks for the great response Ken.