The Omron E3S-GS3E4 2M is a fixed-focus photoelectric sensor from the E3S-G series, using an infrared LED to detect opaque and translucent objects at a 3 cm range. The metal housing makes it suited for production lines where mechanical shock or coolant splash is a concern. Power supply is 12–24 VDC, draws 40 mA max, and the output responds in 1 ms – enough for counting or presence checking on a moderate-speed conveyor.
The E3Z-LL61 is a distance-settable background-suppression (BGS) sensor with a red laser diode and adjustable range up to 300 mm on white paper. The E3S-GS3E4 2M is a fixed-focus infrared type at 3 cm, non-adjustable. These are different sensing methods and application niches; the E3Z-LL61 cannot drop in as a functional replacement without re-engineering the fixture and sensitivity settings.