Can I expand I/O on the network with additional couplers? No. (Page 41 NX-series Safety Control Unit User’s Manual Z930) Coupler unit is limited to the EtherNET/IP Slave Terminal at the connection. You can add Safety CPU to each coupler with safety. (page 45) Safety I/O Node is listed as EIP instead of a node setting NX Stand Alone Quick Start Guide - Version 3.2 Feb. 27, 2015 Page 25