Key ratings that govern fit
The 24 VDC supply rail must be clean and within tolerance; the PLC itself draws only the current required to drive its internal logic and output relays — no separate backplane power budget to calculate. The 24 digital inputs accept standard 24 VDC sink/source signals; the 16 relay outputs handle up to the rated load per contact (typically 2 A per output, per general FX3 spec — verify the specific curve in the manual for inductive loads). Relay outputs are good for AC or DC loads and simplify field wiring with common terminals, but switch slower than transistor outputs — plan scan cycle and load switching accordingly.