The Omron E3Z-G81 is a grooved-type photoelectric sensor with a through-beam sensing method, designed for detecting objects passing through the 25 mm gap. It switches in 1 ms max and drives up to 100 mA from a 12-24 VDC supply, with selectable light-on/dark-on output. Built-in protection covers reversed supply, short circuits, and mutual interference — no external suppression needed.
Mounts directly into a standard 25 mm groove; the through-beam alignment is fixed by the housing. Response time of 1 ms suits moderate-speed part counting or position detection. Output is a 100 mA open collector with selectable L-ON/D-ON — set by the internal switch; no software configuration. Ambient temperature range -25 to 55°C operating, so it's fine for most machine enclosures but not freezers or ovens.