The external and mounting dimensions of the FX2N-1PG and the FX3U-1PG are identical. However, the electrical specifications and connectable FX programmable controllers (FX3U/FX3UC series) are different. For the positioning function, the starting time of the FX3U-1PG became shorter. For details on the positioning function, refer to Appendix C in the FX3U-1PG User's Manual (Manual number: JY997D47301).