FWIW in general only the CPUs with built in Ethernet can have OPC UA servers. I just trolled through my documentation and from the "PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual", GFK-2222AJ, June 2019 it states:
- RX3i CPE302, CPE305, CPE310, CPE330, CPE400 and CPL410 models support OPC-UA. This feature is pending on RSTi-EP CPE100/CPE115.