The OMRON E3A-R3M2 is a photoelectric sensor that accepts a wide operating voltage range—24…240 V AC or 12…240 V DC—giving it flexibility across line and low-voltage control circuits. The cable-entry connection is typical for panel-mount or machine-wired installations.
The E3Z-LT81 peer has fixed 12–24 VDC supply, no AC; the E3A-R3M2 uses 24–240 V AC or 12–240 V DC, requiring a wiring review before substitution.