PLC built in ethernet vs Ethernet module (QJ71E71-100)

[sebasalvarez13 0]

What is the difference between using the PLC built in ethernet function vs mounting an Ethernet module (ex: QJ71E71-100)? Which one is better for communications with non Mitsubishi devices?

[WattUp 29]

One thing I had discovered was using a built in port, with a heavy load process, and running several ethernet connections to trace database, HMIs, other PLC etc.. was when monitoring the code, it would overwhelm the built in port and shut down connections. 

We switched the external traffic to a -100 card, and all communication issues were resolved.