When connected via 10BASE-T, you can replace it. There is no need to change the system definition. Before replacement, set the switches on the front of the NP1L-FL3 module such as the FL-net node No. selection switch according to those on NP1L-FL2. (NP1L-FL3 supports FL-net Ver.2 and has one port of 10BASE-T/100BASE-TX interface (10M/100Mbps auto-changeover). It is possible to use NP1L-FL3 with NP1L-FL2 in 10Mbps communication.)